Glucose Transport Activity Research Articles

The impact of hypoxic training at different altitudes on human physiology, biochemistry, and cytogenetics

This study investigated the impact of dosed hypoxic normobaric exercises on the physio-biochemical parameters of blood and lymph circulation, as well as cytogenetic changes in red blood cells (RBC), using a Sprague Dawley Rat Model. Hypoxic training was conducted in an animal hypoxic chamber. The session lasted 34-35 minutes. The O2 content was 20.5% at the beginning of the session; then, it dropped to 14.8% within 4-5 minutes, corresponding to a rise to an altitude of 2,900-3,000 m, and was maintained at that level until the end of the session. The hypoxic training cycle increased the RBC count by 4.1%, the hemoglobin count by 4.2%, the blood oxygen capacity by 8.3%, the circulating blood volume by 16.7%, and interstitial metabolism and lymph circulation by 30.6%. A cytogenetic study revealed an increase in erythropoiesis-reticulocyte count by 40.3% and a slightly higher frequency of micronucleated erythrocytes. We observed economization of the heart, respiration, activation of glucose transport by 33.5%, increased lipid utilization, and increased antioxidant protection. These parameters especially changed when hypoxic training was combined with physical activity. Hypoxic training with physical activity expands the body’s compensatory and adaptive capabilities by increasing the reserves of the respiratory, cardiovascular, and lymphatic systems.

Dietary supplementation of microencapsulated botanicals and organic acids enhances the expression and function of intestine epithelial digestive enzymes and nutrient transporters in broiler chickens

Organic acids and botanicals have shown protective effects on gut barrier and against inflammation in broilers. However, their effects on intestinal digestive enzymes and nutrients transporters expression and functions have not been fully studied. The objective of this study was to understand how a microencapsulated blend of botanicals and organic acids affected intestinal enzyme activities and nutrient transporters expression and functions in broilers. A total of 288 birds were assigned to a commercial control diet or diet supplemented with 500 g/MT (metric ton) of the microencapsulated additive. Growth performance was recorded weekly. At d 21 and d 42, jejunum and ileum were isolated for enzyme (maltase, sucrase, and aminopeptidase) and transporter (SGLT1, GLUT2, GLUT1, EAAT3, B0AT1, and PepT1) analyses. Jejunum specific nutrients (glucose, alanine, and glutamate) transport activities were evaluated by Ussing chamber. Protein expression of nutrient transporters in small intestine were measured in mucosa and brush-border membrane (BBM) samples by western blot. Intestinal gene expression of the transporters was determined by RT-PCR. Statistical analysis was performed using Student's t-test comparing the supplemented diet to the control. The feed efficiency was significantly improved through the study period in the supplemented group (P ≤ 0.05). Significant changes of intestinal histology were shown in both jejunum (P ≤ 0.10) and ileum (P ≤ 0.05) after 21 d of treatment. At d21, jejunal maltase activity was upregulated (P ≤ 0.10). The Ussing chamber transport of glucose and alanine was increased, which was in line with increased gene expression (GLUT2, GLUT1, EAAT3, and B0AT1) (P ≤ 0.10 and P ≤ 0.05, respectively) and BBMV protein levels (B0AT1, P < 0.10). At d21, ileal sucrase and maltase activities were upregulated (P ≤ 0.05). Increased expressions of GLUT1, EAAT3, and B0AT1 were observed in both mRNA and protein levels (P ≤ 0.05). Similar pattern of changes was also shown at d42 of age. Our results suggest that feeding microencapsulated additives improves intestinal nutrient digestion and transporter expression and function in broilers, thereby enhancing feed efficiency.

Differential Mitochondrial Adaptation of the Slow and Fast Skeletal Muscles by Endurance Running Exercise in Streptozotocin-Induced Diabetic Mice.

The skeletal muscle is the main organ responsible for insulin action, and glucose disposal and metabolism. Endurance and/or resistance training raises the number of mitochondria in diabetic muscles. The details of these adaptations, including mitochondrial adaptations of the slow and fast muscles in diabetes, are unclear. This study aimed to determine whether exercise training in streptozotocin (STZ)-induced mice leads to differential adaptations in the slow and fast muscles, and improving glucose clearance. Eight-week-old mice were randomly distributed into normal control (CON), diabetes (DM), and diabetes and exercise (DM+Ex) groups. In the DM and DM+Ex groups, mice received a freshly prepared STZ (100 mg/kg) intraperitoneal injection on two consecutive days. Two weeks after the injection, the mice in the groups ran on a treadmill for 60 min at 20 m/min for a week and subsequently at 25 m/min for 5 weeks (5 days/week). The analyses indicated that running training at low speed (25 m/min) enhanced mitochondrial enzyme activity and expression of lactate and glucose transporters in the plantaris (low-oxidative) muscle that improved whole-body glucose metabolism in STZ-induced diabetic mice. There were no differences in glucose transporter expression levels in the soleus (high-oxidative) muscle. The endurance running exercise at 20-25 m/min was sufficient to induce mitochondrial adaptation in the low-oxidative muscles, but not in the high-oxidative muscles, of diabetic mice. In conclusion, the present study indicated that running training at 25 m/min improved glucose metabolism by increasing the mitochondrial enzyme activity and glucose transporter 4 and monocarboxylate transporter 4 protein contents in the low-oxidative muscles in STZ-induced diabetic mice.

A systematic review of normal tissue neurovascular unit damage following brain irradiation-Factors affecting damage severity and timing of effects.

Radiotherapy is key in the treatment of primary and secondary brain tumors. However, normal tissue is inevitably irradiated, causing toxicity and contributing to cognitive dysfunction. The relative importance of vascular damage to cognitive decline is poorly understood. Here, we systematically review the evidence for radiation-induced damage to the entire neurovascular unit (NVU), particularly focusing on establishing the factors that influence damage severity, and timing and duration of vascular effects relative to effects on neural tissue. Using PubMed and Web of Science, we searched preclinical and clinical literature published between January 1, 1970 and December 1, 2022 and evaluated factors influencing NVU damage severity and timing of NVU effects resulting from ionizing radiation. Seventy-two rodents, 4 canines, 1 rabbit, and 5 human studies met inclusion criteria. Radiation increased blood-brain barrier (BBB) permeability, reduced endothelial cell number and extracellular matrix proteoglycans, reduced tight junction proteins, upregulated cellular adhesion molecule expression, reduced activity of glucose and BBB efflux transporters and activated glial cells. In the brain parenchyma, increased metalloproteinases 2 and 9 levels, demyelination, cell death, and inhibited differentiation were observed. Effects on the vasculature and neural compartment were observed across acute, delayed, and late timepoints, and damage extent was higher with low linear energy transfer radiation, higher doses, lower dose rates, broader beams, and in the presence of a tumor. Irradiation of normal brain tissue leads to widespread and varied impacts on the NVU. Data indicate that vascular damage is in most cases an early effect that does not quickly resolve. More studies are needed to confirm sequence of damages, and mechanisms that lead to cognitive dysfunction.

Metabolic effects of training with blood flow restriction

Relevance. Training with limited blood flow, which is performed with partial vascular occlusion using inflatable cuffs, can cause an increase in skeletal muscle mass and strength, similar to those observed with classical high-intensity training with weights, although with a noticeably lower mechanical load. Performing a load with a restriction of blood flow leads to the accumulation of metabolites, recruitment of motor neurons with a higher excitation threshold, edema of muscle cells, an increase in the concentration of reactive oxygen species, which, in turn, contributes to hypertrophy of muscle fibers, increased muscle strength, mitochondrial biogenesis, angiogenesis, increased activity of glucose transporters. Based on this, training with limited blood flow should have a positive effect on metabolic health.The aim of the study is a theoretical analysis of the metabolic effects of blood flow restriction training in healthy individuals and in clinical populations.Methods and organization of the study - this review examines the metabolic effects of TOK in both healthy and clinical populations.Conclusions. BFR can be considered as a potential method for improving muscle function and metabolism of glucose, triglycerides and fatty acids.

182 Evaluation of the effects of F18 enterotoxigenic Escherichia coli intestinal attachment in nursery pigs

Abstract Enterotoxigenic Escherichia coli (ETEC) infections are a leading cause of post-weaning diarrhea and poor performance in nursery pigs. ETEC fimbriae regulate binding to epithelial cells and subsequent intestine colonization, commonly F18 in post-weaned pigs. The objective of this study was to evaluate F18 ETEC ileal attachment in relation to growth performance and intestinal integrity and function around peak infection. Following 10 d of acclimation to a common diet, 24 individually housed, mixed sex weaned pigs [initial body weight (BW) = 5.7 ± 0.44 kg] were randomly allotted across 4 treatment groups (n=6/treatment). On day post inoculation (dpi) 0, pigs were non-inoculated (CON) or orally inoculated with 5 mL of F18 ETEC (LT, STb, Stx2, STx2e positive) at either 107 colony-forming units [CFU)/mL (LOW), 108 CFU/mL (MED] or 109 CFU/mL (HIGH). Over a 5-dpi period, fecal scores [scale: 0 (dry) – 3 (watery)] and feed intakes were measured daily. Body weights were recorded on dpi 0 and 5 to calculate average daily gain (ADG), average daily feed intake (ADFI) and gain to feed ratio (G:F). On dpi 5, all pigs were euthanized, ileal contents and feces was assessed for F18 gene abundance via PCR, and fixed ileal sections were evaluated for morphology changes, stem cell proliferation (Ki67), and F18 ETEC attachment via in situ hybridization. Further, ex vivo ileal tissue integrity and function was assessed via Ussing chambers by measuring transepithelial resistance (TER), 4.4 kDa FITC-Dextran (FD4) flux and active glucose and glutamine transport. Pig was considered the experimental unit, and data were analyzed for the fixed effects of treatment. Over this 5 dpi challenge period, ADG, ADFI, and G:F did not differ between treatments (P &amp;gt; 0.05). Compared with the CON, mean fecal scores were greatest in MED followed by the LOW and HIGH treatments (P = 0.028). Ileal pH tended to be greater in the HIGH compared with the MED, LOW and CON (7.8, 7.6, 7.5 and 7.3, respectively, P = 0.08). Compared with the CON, decreased Ct values were reported for the LOW, MED, and HIGH groups for fecal (32, 19, 18, 20, respectively; P &amp;lt; 0.001) and ileal (28, 19, 19, 18, respectively; P = 0.019) F18 gene abundances, respectively. Ileal F18 attachment was greatest in the HIGH group compared with CON, with LOW and MED being intermediate (P = 0.011). The immunohistochemistry stem cell marker Ki67 was lleast in HIGH compared with CON, LOW and MED treatments (P &amp;lt; 0.01). Ileal histology, active glucose and glutamine, TER and FD4 did not differ (P &amp;gt; 0.05). F18 attachment was negatively correlated with ileal (R = -0.706, P &amp;lt; 0.001) and fecal (R = -0.713, P &amp;lt; 0.001) F18 CT values, and positively correlated with ileal pH (R = 0.536, P &amp;lt; 0.01). In conclusion, F18 ileal attachment increased as challenge dose increased. However, at 5-dpi no effect on growth performance or ileal function and integrity was observed.

Post-click labeling enables highly accurate single cell analyses of glucose uptake ex vivo and in vivo

Cellular glucose uptake is a key feature reflecting metabolic demand of cells in physiopathological conditions. Fluorophore-conjugated sugar derivatives are widely used for monitoring glucose transporter (GLUT) activity at the single-cell level, but have limitations in in vivo applications. Here, we develop a click chemistry-based post-labeling method for flow cytometric measurement of glucose uptake with low background adsorption. This strategy relies on GLUT-mediated uptake of azide-tagged sugars, and subsequent intracellular labeling with a cell-permeable fluorescent reagent via a copper-free click reaction. Screening a library of azide-substituted monosaccharides, we discover 6-azido-6-deoxy-D-galactose (6AzGal) as a suitable substrate of GLUTs. 6AzGal displays glucose-like physicochemical properties and reproduces in vivo dynamics similar to 18F-FDG. Combining this method with multi-parametric immunophenotyping, we demonstrate the ability to precisely resolve metabolically-activated cells with various GLUT activities in ex vivo and in vivo models. Overall, this method provides opportunities to dissect the heterogenous metabolic landscape in complex tissue environments.

Plasma membrane-localized hexose transporter OsSWEET1b, affects sugar metabolism and leaf senescence.

OsSWEET1b is a hexose transporter protein, which localized in cell membranes and interacting with itself to form homodimer and knockout of OsSWEET1b resulted in reduced leaves sugar content and accelerating leaf senescence. In the rice genome, the SWEET gene family contains 21 homologous members, but the role of some of them in rice growth and development is still unknown. The function of the sugar transporter OsSWEET1b protein in rice was identified in this research. Expression analysis showed that the expression levels of OsSWEET1b in leaves were higher than that in other tissues. The hexose transport experiment confirmed that OsSWEET1b has glucose and galactose transporter activity in yeast. Subcellular localization indicates that OsSWEET1b protein was targeted to the plasma membrane and BiFC analysis showed that OsSWEET1b interacts with itself to form homodimers. Functional analysis demonstrated that the ossweet1b mutant plants were have reduced the sucrose, glucose, fructose, starch and galactose contents, and induced carbon starvation-related gene expression, which might lead to carbon starvation in leaves at filling stage. The ossweet1b knockout plants showed decreased chlorophyll content and antioxidant enzyme activity, and increased ROS accumulation in leaves, leading to leaf cell death and premature senescence phenotype at filling stage. In ossweet1b mutants, the leaf senescence-related gene expression levels were increased and the abundance of photosynthesis-related proteins was decreased. Loss of OsSWEET1b were affected the starch, sucrose metabolism and carbon fixation in photosynthetic organelles pathway by RNA-seq analysis. The destruction of OsSWEET1b function will cause sugar starvation, decreased photosynthesis and leaf senescence, which leading to reduced rice yield. Collectively, our results suggest that the OsSWEET1b plays a key role in rice leaves carbohydrate metabolism and leaf senescence.

Sphingosine-1-phosphate suppresses GLUT activity through PP2A and counteracts hyperglycemia in diabetic red blood cells

Red blood cells (RBC) are the major carriers of sphingosine-1-phosphate (S1P) in blood. Here we show that variations in RBC S1P content achieved by altering S1P synthesis and transport by genetic and pharmacological means regulate glucose uptake and metabolic flux. This is due to S1P-mediated activation of the catalytic protein phosphatase 2 (PP2A) subunit leading to reduction of cell-surface glucose transporters (GLUTs). The mechanism dynamically responds to metabolic cues from the environment by increasing S1P synthesis, enhancing PP2A activity, reducing GLUT phosphorylation and localization, and diminishing glucose uptake in RBC from diabetic mice and humans. Functionally, it protects RBC against lipid peroxidation in hyperglycemia and diabetes by activating the pentose phosphate pathway. Proof of concept is provided by the resistance of mice lacking the S1P exporter MFSD2B to diabetes-induced HbA1c elevation and thiobarbituric acid reactive substances (TBARS) generation in diabetic RBC. This mechanism responds to pharmacological S1P analogues such as fingolimod and may be functional in other insulin-independent tissues making it a promising therapeutic target.

Molecular Cloning, Expression Analysis, and Functional Analysis of Nine IbSWEETs in Ipomoea batatas (L.) Lam

Sugar Will Eventually be Exported Transporter (SWEET) genes play an important regulatory role in plants’ growth and development, stress response, and sugar metabolism, but there are few reports on the role of SWEET proteins in sweet potato. In this study, nine IbSWEET genes were obtained via PCR amplification from the cDNA of sweet potato. Phylogenetic analysis showed that nine IbSWEETs separately belong to four clades (Clade I~IV) and contain two MtN3/saliva domains or PQ-loop superfamily and six~seven transmembrane domains. Protein interaction prediction showed that seven SWEETs interact with other proteins, and SWEETs interact with each other (SWEET1 and SWEET12; SWEET2 and SWEET17) to form heterodimers. qRT-PCR analysis showed that IbSWEETs were tissue-specific, and IbSWEET1b was highly expressed during root growth and development. In addition to high expression in leaves, IbSWEET15 was also highly expressed during root expansion, and IbSWEET7, 10a, 10b, and 12 showed higher expression in the leaves. The expression of SWEETs showed a significant positive/negative correlation with the content of soluble sugar and starch in storage roots. Under abiotic stress treatment, IbSWEET7 showed a strong response to PEG treatment, while IbSWEET10a, 10b, and 12 responded significantly to 4 °C treatment and, also, at 1 h after ABA, to NaCl treatment. A yeast mutant complementation assay showed that IbSWEET7 had fructose, mannose, and glucose transport activity; IbSWEET15 had glucose transport activity and weaker sucrose transport activity; and all nine IbSWEETs could transport 2-deoxyglucose. These results provide a basis for further elucidating the functions of SWEET genes and promoting molecular breeding in sweet potato.

A Bioinspired Flexible Sensor for Electrochemical Probing of Dynamic Redox Disequilibrium in Cancer Cells.

Malignant tumors pose a serious risk to human health. Ascorbic acid (AA) has potential for tumor therapy; however, the mechanism underlying the ability of AA to selectively kill tumor cells remains unclear. AA can cause redox disequilibrium in tumor cells, resulting in the release of abundant reactive oxygen species, represented by hydrogen peroxide (H2 O2 ). Therefore, the detection of H2 O2 changes can provide insight into the selective killing mechanism of AA against tumor cells. In this work, inspired by the ion-exchange mechanism in coral formation, a flexible H2 O2 sensor (PtNFs/CoPi@CC) is constructed to monitor the dynamics of H2 O2 in the cell microenvironment, which exhibits excellent sensitivity and spatiotemporal resolution. Moreover, the findings suggest that dehydroascorbic acid (DHA), the oxidation product of AA, is highly possible the substance that actually acts on tumor cells in AA therapy. Additionally, the intracellular redox disequilibrium and H2 O2 release caused by DHA are positively correlated with the abundance and activity of glucose transporter 1 (GLUT1). In conclusion, this work has revealed the potential mechanism underlying the ability of AA to selectively kill tumor cells through the construction and use of PtNFs/CoPi@CC. The findings provide new insights into the clinical application of AA.

Purified Polysaccharides Extracted from Gray Oyster Mushroom (Pleurotus sajor-caju (Fr.) Sing.) Stimulate Glucose Uptake in C2C12 Myotubes through the activation of AMP-Activated Protein Kinase (AMPK) and Glucose Transporter 1 (GLUT1) Proteins

The grey oyster mushroom [Pleurotus sajor-caju (Fr.) Sing.], an edible mushroom, has been known as a source of bioactive compounds, including polysaccharides. Polysaccharides from this mushroom have been shown to possess antidiabetic activity both in vivo and in vitro. However, antidiabetic mechanism of partially purified or purified polysaccharides from the gray oyster mushroom has not been characterized. In this study, we extracted and purified polysaccharides from gray oyster mushrooms and used them to investigate the antidiabetic mechanism in the context of C2C12 myotubes. Using Fourier Transform Infrared spectroscopy (FTIR) analysis and enzymatic assay, we showed that the polysaccharide sample, namely 9S1-1, contains b-glucose, a-glucose, and mannose as the monosaccharide composition, and b-glucan is the major type of polysaccharide in the sample. This 9S1-1 sample dose-dependently stimulated glucose uptake in C2C12 myotubes. Further analysis showed that the sample activated the AMP-activated protein kinase (AMPK) but not Akt serine/threonine kinase (AKT) phosphorylation, suggesting that the stimulation is AMPK-dependent. Moreover, we showed that compound c, an inhibitor of AMPK, inhibited glucose uptake in 9S1-1-stimulated cells, confirming the requirement of AMPK in the glucose uptake activated by the 9S1-1 sample. In addition, it promoted glucose transporter protein type 1 (GLUT1) but not GLUT4 protein expression. These results suggest that GLUT1 may be responsible for the stimulation of glucose uptake in 9S1-1-activated cells. Together, these data illustrate the antidiabetic mechanism of polysaccharides isolated from the gray oyster mushroom and the potential use of the polysaccharide as an antidiabetic agent.

The role of salt bridge networks in the stability of the yeast hexose transporter 1

BackgroundThe yeast S. cerevisiae preferably metabolizes glucose through aerobic glycolysis. Glucose transport is facilitated by multiple hexose transporters (Hxts), and their expression and activity are tightly regulated by multiple mechanisms. However, detailed structural and functional analyses of Hxts remain limited, largely due to the lack of crystal structure. MethodsHomology modeling was used to build a 3D structural model for the yeast glucose transporter Hxt1 and investigate the effects of site directed mutations on Hxt1 stability and glucose transport activity. ResultsThe conserved salt bridge-forming residues observed in the human Glut4 and the yeast glucose receptor Rgt2 were identified within and between the two 6-transmembrane spanning segments of Hxt1. Most of the RGT2 mutations that disrupt the salt bridge networks were known to cause constitutive signal generation, whereas the corresponding substitutions in HXT1 were shown to decrease Hxt1 stability. While substitutions of the two residues in the salt bridge 2 in Glut4—E329Q and E393D—were reported to abolish glucose transport, the equivalent substitutions in Hxt1 (D382Q and E454D) did not affect Hxt1 glucose transport activity. ConclusionsSubstitutions of equivalent salt bridge-forming residues in Hxt1, Rgt2, and Glut4 are predicted to lock them in an inward-facing conformation but lead to different functional consequences. General significanceThe salt bridge networks in yeast and human glucose transporters and yeast glucose receptors may play different roles in maintaining their structural and functional integrity.

GLUT1 Mediates the Metabolic Reprogramming and Inflammation of CCR2$^+$ Monocytes/Macrophages from Patients with DCM.

Macrophages expressing CC chemokine receptor 2 (CCR2) possess characteristics and performance akin to M1 polarized macrophages, which promote inflammation. Advanced heart failure (HF) patients with higher abundance of CCR2+ macrophages are more likely to experience adverse remodeling. The precise mechanism of CCR2+ macrophages in how they affect the progression of dilated cardiomyopathy remains unknown. Cardiac biopsy samples from dilated cardiomyopathy patients (DCM) were used for immunohistochemistry and immunofluorescence staining. PCR is employed to identify the IL-1β, IL-6, TNF-α, TGF-β, MMP2, MMP9, PKM1, PKM1, GLUT1, GLUT2, GLUT3, GLUT4, PDK1, PFKFB3, PFK1 and HK2 mRNA expression of CCR2+ monocytes/macrophages from the peripheral blood of DCM patients. Seahorse was used to evaluate the oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) of CCR2+ monocytes/macrophages. 2-DG was used to simulate a lack of glucose. Lentivirus containing GLUT1 inhibitory sequence was used to knockdown GLUT1 gene expression of CCR2+ monocytes/macrophages. Western Blot and immunofluorescence staining was used to evaluate the expression of NLRP3. Immunostaining results of cardiac biopsy tissue from dilated cardiomyopathy (DCM) patients demonstrated that the progression to HF was associated with an increase in the number of CCR2+ macrophages. PCR results demonstrated that CCR2 monocytes and macrophages derived from the blood of DCM patients expressed elevated levels of inflammatory factors and up regulation of glycolysis related genes. In addition, OCR and glucose uptake experiments confirmed that increased glucose uptake of these cells was associated with greater inflammation and correlated with a worsening of cardiac function. limiting the glucose supply to CCR2+ monocytes and macrophages, or suppressing the activity of glucose transporter 1 (GLUT1) could reduce inflammation levels. These results suggest that CCR2+ monocytes and macrophages rely on metabolic reprogramming to trigger inflammatory response and contribute to myocardial injury and the progression of DCM.

The Impact of Tumor-Associated Macrophages Found at Mammary Carcinoma Sites is Dependent Upon the Tumor Type

ABSTRACT Background Previously, we reported that tumor-associated macrophages (TAM) at early sites of mammary carcinoma showed a decrease in ATP production rate and a higher dependence on oxidative phosphorylation. Methods Since these changes can result from activation of AMP-activated protein kinase (AMPK) and glucose transporter 1 (Glut1) during metabolic stress, we investigated whether the TAM showed increased expression of ampk and glut1, as well as another indicator of metabolic stress, pkm2. Indeed, the TAM exhibited significant expression of pkm2, glut1, and ampk. Results Bone marrow-derived macrophages (BMDM) co-cultured with 4T1, EMT6, and 168 in vitro similarly showed increased expression of pkm2, glut1, and ampk. Moreover, lactate, which is expressed at significant levels by all three tumors, induced expression of these same genes in BMDM suggesting that lactate may induce a metabolic stress response in these TAM. Yet, the three different mammary carcinoma models benefited from different targeting strategies. Macrophage depletion studies revealed that the TAM contributed to growth of the EMT6 tumor and metastasis of the 4T1 tumor. Targeting the stress response with the Integrated Stress Response Inhibitor (ISRIB), which targets eIF2, impacted 168 tumor progression, and ISRIB as well as FX-11, which targets lactate dehydrogenase, impacted 4T1 tumor progression and metastasis. Conclusions Collectively, these data demonstrate that targeting TAM or metabolism at early tumor sites can impact tumor progression. However, variability in the responses underscore the fact that the impact of macrophages differs even within three different syngeneic mammary carcinoma models.

Dynamic 2-deoxy-D-glucose-enhanced multispectral optoacoustic tomography for assessing metabolism and vascular hemodynamics of breast cancer

Clinical tools for measuring tumor vascular hemodynamics, such as dynamic contrast-enhanced MRI, are clinically important to assess tumor properties. Here we explored the use of multispectral optoacoustic tomography (MSOT), which has a high spatial and temporal resolution, to measure the intratumoral pharmacokinetics of a near-infrared-dye-labeled 2-Deoxyglucose, 2-DG-800, in orthotropic 2-LMP breast tumors in mice. As uptake of 2-DG-800 is dependent on both vascular properties, and glucose transporter activity – a widely-used surrogate for metabolism, we evaluate hemodynamics of 2-DG-MP by fitting the dynamic MSOT signal of 2-DG-800 into two-compartment models including the extended Tofts model (ETM) and reference region model (RRM). We showed that dynamic 2-DG-enhanced MSOT (DGE-MSOT) is powerful in acquiring hemodynamic rate constants, including Ktrans and Kep, via systemically injecting a low dose of 2-DG-800 (0.5 µmol/kg b.w.). In our study, both ETM and RRM are efficient in deriving hemodynamic parameters in the tumor. Area-under-curve (AUC) values (which correlate to metabolism), and Ktrans and Kep values, can effectively distinguish tumor from muscle. Hemodynamic parameters also demonstrated correlations to hemoglobin, oxyhemoglobin, and blood oxygen level (SO2) measurements by spectral unmixing of the MSOT data. Together, our study for the first time demonstrated the capability of DGE-MSOT in assessing vascular hemodynamics of tumors.

Nimbin analogs stimulate glucose uptake and glycogen storage in the insulin signalling cascade by enhancing the IRTK, PI3K and Glut-4 mechanism in myotubes

BackgroundDiabetes Mellitus is a metabolic disorder characterized by insulin dysfunction or failure of the pancreatic β-cells to produce insulin resulting in hyperglycemia. Adverse effects of hyperglycemic conditions continue to be common, reducing treatment adherence. Intensified therapies are required for the constant loss of endogenous islet reserve. AimThis study aimed to evaluate the effect of Nimbin semi-natural analogs (N2, N5, N7, and N8) from A. indica on high glucose-induced ROS and apoptosis with insulin resistance in L6 myotubes evaluated along with Wortmannin and Genistein inhibitors and the expression of key genes in the insulin signalling pathway. Materials and methodsThe analogs were screened for anti-oxidant and anti-diabetic activity using cell-free assays; The ability of analogs to suppress ROS and prevent apoptosis induced by High glucose and uptake glucose and glycogen storage in L6 myotubes was evaluated using DCFH-DA, AO-PI and 2NBDG staining. Further, the glucose uptake was performed in the presence of Insulin Receptor Tyrosine Kinase (IRTK) inhibitors, and the expression of key genes PI3K, Glut-4, GS and IRTK in the insulin signalling pathway were evaluated. Key findingsThe Nimbin analogs were not toxic to the L6 cells, and the analogs could scavenge ROS and suppress cellular damage induced due to high glucose. Enhanced glucose uptake was observed in N2, N5 and N7 compared to N8. The maximum activity of optimum concentration was found to be 100 μM. The N2, N5 and N7 showed an increase in IRTK, which is equivalent to insulin at a concentration of 100 µM. The IRTK inhibitor with Genistein (50 µM) confirmed the presence of IRTK-dependent glucose transport activation; it also supports the expression of key genes PI3K, Glut-4, GS and IRTK. As a result of PI3K activation, N2, N5, and N7 exhibited the insulin-mimetic effect by enhancing glucose uptake and glycogen conversion regulating glucose metabolism. SignificanceN2, N5 and N7 could therapeutically benefit against insulin resistance by glucose metabolism modulation, insulin secretion, β-cell stimulation, inhibition of gluconeogenic enzymes and ROS protection.

Cells sorted off hiPSC-derived kidney organoids coupled with immortalized cells reliably model the proximal tubule

Of late, numerous microphysiological systems have been employed to model the renal proximal tubule. Yet there is lack of research on refining the functions of the proximal tubule epithelial layer—selective filtration and reabsorption. In this report, pseudo proximal tubule cells extracted from human-induced pluripotent stem cell-derived kidney organoids are combined and cultured with immortalized proximal tubule cells. It is shown that the cocultured tissue is an impervious epithelium that offers improved levels of certain transporters, extracellular matrix proteins collagen and laminin, and superior glucose transport and P-glycoprotein activity. mRNA expression levels higher than those obtained from each cell type were detected, suggesting an anomalous synergistic crosstalk between the two. Alongside, the improvements in morphological characteristics and performance of the immortalized proximal tubule tissue layer exposed, upon maturation, to human umbilical vein endothelial cells are thoroughly quantified and compared. Glucose and albumin reabsorption, as well as xenobiotic efflux rates through P-glycoprotein were all improved. The data presented abreast highlight the advantages of the cocultured epithelial layer and the non-iPSC-based bilayer. The in vitro models presented herein can be helpful in personalized nephrotoxicity studies.

Self-assembled human placental model from trophoblast stem cells in a dynamic organ-on-a-chip system.

The placental barrier plays a key role in protecting the developing fetus from xenobiotics and exchanging substances between the fetus and mother. However, the trophoblast cell lines and animal models are often inadequate to recapitulate the key architecture and functional characteristics of human placental barrier. Here, we described a biomimetic placental barrier model from human trophoblast stem cells (hTSCs) in a perfused organ chip system. The placental barrier was constructed by co-culture of hTSCs and endothelial cells on the opposite sides of a collagen-coated membrane on chip. hTSCs can differentiate into cytotrophoblasts (CT) and syncytiotrophoblast (ST), which self-assembled into bilayered trophoblastic epithelium with placental microvilli-like structure under dynamic cultures. The formed placental barrier displayed dense microvilli, higher level secretion of human chorionic gonadotropin (hCG), enhanced glucose transport activity. Moreover, RNA-seq analysis revealed upregulated ST expression and activation of trophoblast differentiation-related signalling pathways. These results indicated the key role of fluid flow in promoting trophoblast syncytialization and placental early development. After exposure to mono-2-ethylhexyl phthalate, one of the endocrine disrupting chemicals, the model showed inhibited hCG production and disturbed ST formation in trophoblastic epithelium, suggesting impaired placental structure and function elicited by environmental toxicants. Collectively, the hTSCs-derived placental model can recapitulate placenta physiology and pathological response to external stimuli in a biomimetic manner, which is useful for the study of placental biology and associated diseases.

Active glucose transport varies by small intestinal region and oestrous cycle stage in mice.

What is the central question of this study? Body mass and food intake change during the female ovarian cycle: does glucose transport by the small intestine also vary? What is the main finding and its importance? We have optimised Ussing chamber methodology to measure region-specific active glucose transport in the small intestine of adult C57BL/6 mice. Our study provides the first evidence that jejunal active glucose transport changes during the oestrous cycle in mice, and is higher at pro-oestrus than oestrus. These results demonstrate adaptation in active glucose uptake, concurrent with previously reported changes in food intake. Food intake changes across the ovarian cycle in rodents and humans, with a nadir during the pre-ovulatory phase and a peak during the luteal phase. However, it is unknown whether the rate of intestinal glucose absorption also changes. We therefore mounted small intestinal sections from C57BL/6 female mice (8-9weeks old) in Ussing chambers and measured active ex vivo glucose transport via the change in short-circuit current (∆Isc ) induced by glucose. Tissue viability was confirmed by a positive ∆Isc response to 100µM carbachol following each experiment. Active glucose transport, assessed after addition of 5, 10, 25 or 45mM d-glucose to the mucosal chamber, was highest at 45mM glucose in the distal jejunum compared to duodenum and ileum (P<0.01). Incubation with the sodium-glucose cotransporter 1 (SGLT1) inhibitor phlorizin reduced active glucose transport in a dose-dependent manner in all regions (P<0.01). Active glucose uptake induced by addition of 45mM glucose to the mucosal chamber in the absence or presence of phlorizin was assessed in jejunum at each oestrous cycle stage (n=9-10 mice per stage). Overall, active glucose uptake was lower at oestrus compared to pro-oestrus (P=0.025). This study establishes an ex vivo method to measure region-specific glucose transport in the mouse small intestine. Our results provide the first direct evidence that SGLT1-mediated glucose transport in the jejunum changes across the ovarian cycle. The mechanisms underlying these adaptations in nutrient absorption remain to be elucidated.