Glucose Transporter Research Articles

6421 Imaging Phenotype May Predict Genotype In Human Pheochromocytoma: Relationships Between Genetic Mutation Clusters, Metabolite Transporter Expression, And Radiotracer Uptake

Abstract Disclosure: I. Sakuma: None. M. Fujimoto: None. D.F. Vatner: None. K. Yokote: None. T. Tanaka: None. Context [1]23I-metaiodobenzylguanidine scintigraphy (MIBG) and [1]8F-fluoro-2-doxy-D-glucose positron emission tomography (FDG-PET) are helpful for the localization of pheochromocytoma. The norepinephrine transporter (NET) and the glucose transporter 1 (GLUT1) are thought to be critical for the uptake of these radioisotopes. NET expression is activated by Paired Like Homeobox (PHOX2) and glucocorticoid receptor (GR) in neuroblastoma cells. Around 70% of pheochromocytomas carry well-known mutations. Pheochromocytoma-associated genes are divided into two clusters: the pseudohypoxia-related cluster 1 and the kinase signaling-related cluster 2. Cluster 1 mutation are associated with noradrenergic pheochromocytomas with an elevated metastatic risk. Cluster 2 tumors demonstrate an adrenergic phenotype with a less aggressive course. How mutations of cluster 1 and cluster 2 impact the expression of NET/GLUT1 and on radiotracer uptake remains unclear. Hypothesis Cluster 1 and cluster 2 will have different effects on the expression of transcription factors associated with chromaffin cell differentiation with resultant differential effects on NET/GLUT1 expression. Methods 42 patients with pheochromocytoma were evaluated by MIBG and FDG-PET. Tumor gene expression was evaluated by real-time qPCR, and mutation analyses were performed by Sanger or next-generation sequencing. Results 88% of tumors were MIBG-avid, and 67% were FDG-avid. The expression of NET in MIBG-negative tumors was 70% lower than in MIBG-positive tumors. The expression of GLUT1 in FDG-PET-negative tumors was 75% lower than in FDG-PET-positive tumors. The expression of NET positively correlated with transcription factors involved in chromaffin cell maturation, including PHOX2A, PHOX2B, GATA binding protein 3 (GATA3), GR, catecholamine synthases, and insulinoma associated 1 (INSM1). The JASPAR database for promoter analysis revealed putative responsive regions of the transcription factors PHOX2A, PHOX2B, GATA3, GR, and INSM1 on the NET gene. Seven patients (16.7%) had mutations in cluster 1, and fourteen patients (33.3%) had mutations in cluster 2. Cluster 2 exhibited elevated NET, PHOX2A, PHOX2B, GATA3, GR, and INSM1 expression levels compared to cluster 1. Cluster 1 showed a higher expression level of GLUT1 and BMP4 that is associated with early chromaffin cell differentiation. Conclusions In pheochromocytomas, MIBG and FDG uptake correlated with the expression levels of NET and GLUT1, respectively. NET expression is associated with chromaffin cell differentiation transcription factor expression. We propose that pheochromocytomas that carry Cluster 1 mutations are more likely to be missed in MIBG due to low NET expression, while pheochromocytomas that carry Cluster 2 mutations are more likely to be missed on FDG-PET due to low GLUT1 expression with a more mature chromaffin cell phenotype. Presentation: 6/2/2024

8780 The Role of Nuclear Receptor Corepressors 1 and 2 on Intestinal Carbohydrate Transport in Mice

Abstract Disclosure: M.J. Ritter: None. I. Amano: None. A.H. van der Spek: None. H.E. Daniel: None. A.N. Hollenberg: None. The nuclear receptor corepressors NCoR1 and NCoR2 are two critical regulators of metabolism that are required for maintaining metabolic homeostasis. Both NCoR1 and NCoR2 (also known as the silencing mediator of retinoic acid and thyroid hormone receptors; SMRT) recruit histone deacetylase 3 (HDAC3) to their deacetylase domain (DAD) to repress nuclear receptor (NR) target gene expression. Interruption of the DAD of NCoR1 in mice leads to lower body weight, decreased whole-body fat mass, insulin sensitization with altered oscillatory patterns of key metabolic genes (1). On the other hand, total body knock-out (KO) of SMRT leads to weight gain, insulin resistance, and hepatic steatosis with an increase in hepatic lipogenesis (2). Previously, we showed that the KO of NCoR1 and SMRT in tandem from adult mice led rapidly to weight loss, hypoglycemia, hypothermia and was lethal. Reductions in intestinal carbohydrate transporters were seen, including sodium-glucose linked transporter-1 (SGLT1), glucose transporter 2 (GLUT2), and glucose transporter 5 (GLUT5) (3). Thus, we hypothesized that NCoR1 and SMRT play unique roles in regulating intestinal carbohydrate metabolism, in turn controlling metabolic parameters including body mass and glucose levels. We then generated a novel model to enable KO of NCoR1 and SMRT throughout intestinal epithelial cells (IECs) in adult mice using a tamoxifen inducible cre under control of the villin 1 promoter. Mice were injected with tamoxifen and body weight and glucose were monitored daily. This was followed by both oral and intraperitoneal glucose tolerance testing (GTT) and metabolic phenotyping. Preliminary data showed that NCoR1 and SMRT KO leads to sustained weight loss and hypoglycemia with 50% survivability. Metabolic phenotyping confirmed reduction in body mass without concomitant reduction in food intake. Oral GTT showed a blunted peak in response to glucose gavage compared to intraperitoneal administration. Gene expression analysis showed reduction in SGLT1, GLUT2, and GLUT5 in addition to changes in metabolic pathways associated with fatty acid metabolism. Here, we show that NCoR1 and SMRT are critical regulators of body mass and glucose in part via their actions on carbohydrate transporters in the intestine. With the global burden of metabolic diseases, including obesity and diabetes, ever-rising, NCoR1 and SMRT represent an overlooked but important area of study to better our understanding of disease processes and identify new targets for treatment. We next aim to determine the functional mechanism by which weight loss and hypoglycemia develop in addition to identifying molecular targets and pathways regulated by NCoR1 and SMRT in IECs.

12527 Determining The Impact Of Dampened Oxidative Stress On Islet Function And Gene Expression During Diabetes Onset In NOD Mice

Abstract Disclosure: K.V. Coutinho: None. H. Shinde: None. J. Feduska: None. K. Burnette: None. S.O. Poole: None. H.M. Tse: None. C.S. Hunter: None. Type 1 diabetes (T1D) arises from autoimmune destruction of insulin-producing pancreatic β-cells. Revealing the mechanisms underlying T1D onset are critical for therapeutic development but not completely understood. NADPH oxidase (NOX) generates superoxide, a precursor of reactive oxygen species (ROS), to regulate cell survival, differentiation, signaling, and autoimmune responses in T1D. NOD (Non-Obese Diabetic) mice spontaneously develop T1D, featuring increased cytokine/chemokine synthesis, inflammatory responsive macrophages and T cells, and ROS. Here, we harness NOD mice deficient in NOX-derived superoxide (NOD.Ncf1m[1]J), which have significantly lower T1D incidence. However, the impacts on islet β-cells in this T1D resistant model are unknown. We assessed a time course of glucose homeostasis between 6-20 weeks (W), spanning the onset T1D in NOD mice. Surprisingly, comparative glucose tolerance testing (GTT) in NOD.Ncf1m[1]J mice revealed increased glucose intolerance at 10W with no differences at 6, 14, and 20W as compared to NOD. Insulin tolerance was similar between the two models at all stages examined. This suggests superoxide production is necessary for β-cell function, despite that NOD.Ncf1m[1]J mice are T1D resistant. To understand islet transcriptomic changes between NOD and NOD.Ncf1m[1]J mice, we conducted comparative bulk islet RNA sequencing from 6 to 20W. Principal component analysis was applied to ensure differences between genotypes at each timepoint. Quality control methods within the Nextflow core pipeline were used to ensure sample quality. As expected, NOD.Ncf1m[1]J mice had decreased Ncf1 and immune response-related mRNA levels. Expression of T-cell exhaustion (Pdcd1, Lag3, and Tigit) genes remained level in NOD mice, but had significantly lower expression at 6W in NOD.Ncf1m[1]J mice. Interestingly, Ctla4, encoding a gene product that inhibits T-cell function, was upregulated at 14W in NOD.Ncf1m[1]J mice. Furthermore, GO analysis of downregulated NOD.Ncf1m[1]J gene sets include T-cell activation, response to IFN-β and IFN-γ at 6W, and decreased cytokine production at 20W. Supporting the dysregulation of β-cell function, Bace2, encoding a protease that limits β-cell function and mass, was upregulated with NOD. Ncf1m[1]J. Additionally, 14W β-cell function gene expression was decreased in the NOD.Ncf1m[1]J mice, including Slc2a2, which encodes the β-cell GLUT2 glucose transporter, and Glp1r, which is involved in preserving β-cell mass and function. Taken together, NOX-derived superoxide, whose loss decreases T1D incidence, may also dampen β-cell gene expression and function. Future directions will include comparative NOD and NOD.Ncf1m[1]J single cell transcriptomics to determine cell type specific transcriptional signatures between islet and immune cell subtypes. Presentation: 6/2/2024

7284 Ablation of hexose-6-phosphate dehydrogenase in mice causes skeletal muscle atrophy and dramatically impairs exercise capacity

Abstract Disclosure: M. Zogg: None. A.D. Grötsch: None. J. Birk: None. P. Pelczar: None. J. Bouitbir: None. A. Odermatt: None. Hexose-6-phosphate dehydrogenase (H6PD) catalyzes the first two steps of the pentose-phosphate pathway (PPP) within the endoplasmic reticulum (ER), generating the redox equivalent NADPH. It has been shown that mice lacking H6PD develop defects mainly in skeletal muscles [1]. Nevertheless, the mechanisms underlying the myopathy in H6PD KO mice is unknown. Here, we further assessed muscle responses to H6PD deficiency and aimed to uncover the mechanisms that may cause myopathy in mice. We conducted a detailed characterization of the muscle structure and function as well as energy metabolism in oxidative and glycolytic muscles of H6PD KO mice. At the age of 15 weeks, H6PD KO mice displayed lower body weight than WT mice, despite similar food and water intake. Grip strength was significantly lower in H6PD KO than in WT mice. This was associated with decreased weight of the mixed (gastrocnemius, quadriceps) and fast fiber type rich muscles of the hind leg (extensor digitorum longus, tibialis anterior) in H6PD KO animals. Atrogin1 and Murf1 mRNA expression, markers of atrophy, increased only in the white (glycolytic) quadriceps. In this context, fast-twitch fibers in WT mice displayed higher H6pd mRNA expression than slow-twitch fibers. Electron microscopy analysis of red and white gastrocnemius muscles displayed the presence of large intramyofibrillar vacuoles, and morphologic changes of the sarcoplasmic reticulum and mitochondria in H6PD KO muscle. Metabolically, H6PD KO muscles presented an accumulation of glycogen granules and significantly decreased mRNA expression of glucose transporter Glut4, glucose-6-phosphate transporter G6pt and glycogen phosphorylase Pygm. The exercise capacity, measured by maximal running distance, decreased by more than 50% in H6PD KO mice. Upon exercise, both WT and H6PD KO animals were able to mobilize the majority of glycogen stored in their muscles. However, immediately after exercise, there was a significant increase in plasma lactate and glucose levels in H6PD KO animals. Disturbances in glucose metabolism were further supported by in vitro experiments using stable C2C12 H6PD KO myoblasts, revealing a shift in basal state mitochondrial fuel oxidation usage from glucose to fatty acid and glutamine in metabolic dependency assays. In conclusion, our findings revealed that H6PD seems to play a key role in proper function and energy metabolism of skeletal muscles.

8418 Association of GLP-1 Receptor Agonists and SGLT-2 Inhibitors with Major Adverse Cardiovascular Events and Serious Liver Events among Patients with Type 2 Diabetes and MASLD

Abstract Disclosure: A. Kutz: None. D.J. Wexler: None. J. Liu: None. J.M. Paik: None. E. Patorno: None. Introduction and study question Little is known about the cardiovascular (CV) and hepatic effectiveness of glucagon-like peptide 1 receptor agonists (GLP-1 RA) and sodium–glucose cotransporter 2 inhibitors (SGLT-2i) in people with type 2 diabetes (T2D) and known metabolic dysfunction-associated steatotic liver disease (MASLD) in clinical practice. We assessed the comparative CV and hepatic effectiveness and the safety of GLP-1 RA and SGLT-2i in people with T2D and prevalent MASLD. Methodology Using pooled data from Medicare fee-for-service (2013–2020) and a large U.S. health insurance database (2013-June 2022), we conducted two propensity-score fine stratification weighted cohort studies including adults with T2D and a diagnosis of MASLD who initiated GLP-1RA, SGLT-2i, or dipeptidyl peptidase 4 inhibitors (DPP-4i, reference). Using Cox proportional hazards models, we assessed the primary CV effectiveness composite outcome of acute myocardial infarction, ischemic stroke, hospitalization for heart failure, or all-cause mortality. The primary hepatic effectiveness outcome was a composite of serious liver events (hospitalization for ascites, spontaneous bacterial peritonitis, hepatorenal syndrome, bleeding esophageal varices, hepatic encephalopathy, or liver transplantation). The safety outcome was a composite of severe adverse events (lower limb amputation, non-vertebral fracture, emergency admission for hypoglycemia, or hospitalization for acute kidney injury, diabetic ketoacidosis [DKA], severe genital or urinary tract infection, acute pancreatitis, or biliary event). Major results Compared with DPP-4i (n=17,084 initiators), the hazard ratio (HR) for the primary CV outcome associated with GLP-1 RA (n=13,666 initiators) was 0.67 (95% CI, 0.56 to 0.81), corresponding to an incidence rate difference (IRD) per 1,000 person-years of -21.6 (95% CI, -26.7 to -16.6). The HR for the primary hepatic outcome was 0.47 (95% CI, 0.25 to 0.90), the IRD -2.1 (95% CI -3.4 to -0.9). Similar CV benefits were observed for SGLT-2i (n=11,108) vs DPP-4i (n=16,979), with a HR for the primary CV outcome of 0.82 (95% CI 0.70–0.96) and an IRD of -11.0 (95% CI -16.2 to -5.8). For the primary hepatic outcome, the HR was 0.81 (95% CI 0.45 to 1.44) and the IRD -1.1 (95% CI -2.4 to 0.3). Severe adverse events were not more frequent with GLP-1RA or SGLT-2i compared with DPP-4i. Interpretation and conclusion Among people with T2D and MASLD, the use of GLP-1 RA or SGLT-2i was associated with fewer CV events, vs DPP-4i, while GLP-1 RA also reduced serious liver events. Compared with DPP-4i, GLP-1RA or SGLT-2i were not associated with higher safety adverse event rates. Presentation: 6/2/2024

7578 SGLT2 Inhibitor Is Associated With A Decreased Risk Of Cerebrovascular Events And Dementia Compared To Thiazolidinedione In Subjects With Type 2 Diabetes

Abstract Disclosure: H. Park: None. S. Park: None. H. Kim: None. D. Byun: None. Subjects with type 2 diabetes (T2D) are at higher risk of developing cerebrovascular disease, cognitive decline, and dementia. Hyperinsulinemia and insulin resistance in the brain have been linked to amyloid beta metabolism, raising the risk of Alzheimer's dementia. Recently, several clinical studies have shown potential beneficial effects of sodium glucose co-transporter-2 (SGLT2) inhibitors, and thiazolidinediones, in the risk of cerebrovascular events and dementia in T2D. This study was aimed to investigate the comparative efficacy of SGLT2 inhibitors and thiazolidinediones in modifying the risk of cerebrovascular events, dementia, and Alzheimer's dementia. Using the common data model, we analyzed patients from December 31, 2011 to December 30, 2022 from 15 hospitals in South Korea. Clinical outcomes between SGLT2 inhibitors and thiazolidinediones were compared using hazard ratios (HRs), with large-scale propensity score matching and a random-effects model applied. Our analyses showed that subjects on SGLT2 inhibitors had a significantly reduced rate of cerebrovascular events (HR 0.2787, 95% CI 0.1882-0.4127, p<0.00001), dementia (HR 0.5395, 95% CI 0.3824-0.7614, p=0.0004), and Alzheimer's dementia (HR 0.586, 95% CI 0.4634-0.7411, p<0.00001), compared to those on thiazolidinediones. In summary, these results suggest that SGLT2 inhibitor administration is associated with a lower risk of cerebrovascular events, dementia, and Alzheimer's dementia compared to thiazolidinedione in subjects with T2D. Further studies are warranted to confirm our findings and elucidate the underlying mechanisms. Presentation: 6/3/2024

Expression of nuclear receptors and glucose metabolic pathway proteins in sebaceous carcinoma: Androgen receptor and monocarboxylate transporter 1 have a key role in disease progression.

Standard systemic treatments are not consistently effective for treating unresectable or advanced sebaceous carcinoma (SC). The present study investigated the pathogenic roles of nuclear receptors (NRs), glucose metabolic dysregulation and immune checkpoint proteins in SC as prognostic markers or therapeutic targets. Patients with pathologically confirmed SC between January 2002 and December 2019 at three university hospitals in South Korea were included in the present study. Immunohistochemistry was performed on paraffin-embedded tumor tissues for glucocorticoid receptors (GR), androgen receptors (AR), estrogen receptors (ER), progesterone receptors (PR), glucose transporter 1 (GLUT1), monocarboxylate transporters (MCT1 and MCT4), CD147, phosphorylated adenosine monophosphate-activated protein kinase (pAMPK) and the immune checkpoint protein, programmed cell death-ligand 1 (PD-L1). The results were semi-quantitatively assessed and the associations of these proteins with various clinicopathological parameters were determined. A total of 39 cases of SC comprising 19 periocular and 20 extraocular tumors were enrolled. NRs were frequently detected in the tumor nuclei, with GR having the highest frequency (89.7%), followed by AR, ER (both 51.3%) and PR (41.0%). Regarding glucose metabolism, CD147, GLUT1 and MCT1 were highly expressed at 100, 89.7 and 87.2%, respectively, whereas MCT4 and pAMPK expression levels were relatively low at 38.5 and 35.9%, respectively. Membranous expression of PD-L1 was detected in five cases (12.8%), four of which were extraocular. In the multivariate analysis, advanced stage, low AR positivity and high MCT1 expression were independent poor prognostic factors for metastasis-free survival (all P<0.05). The present results suggested that hormonal and metabolic dysregulation may be associated with the pathogenesis of SC, and that AR and MCT1 in particular may serve as prognostic indicators and potential therapeutic targets. Additionally, ~10% of SC cases exhibited PD-L1 expression within the druggable range, and these patients are expected to benefit from treatment with immune checkpoint inhibitors.

In Vitro and In Silico Evaluation of Caffeic and Ferulic Acids Involvement in the Translocation of Glucose Transporter 4

Background: Insulin is a key hormone in our systems. Upon binding of insulin to its receptors in fat and muscle tissues, tens of proteins in the insulin signaling pathway are involved in the process of GLUT4 vesicle recruitment to the Plasma Membrane (PM) and the absorption of serum glucose. Deficits in the aforementioned pathway lead to insulin resistance and eventually to Type II Diabetes Mellitus. Objective: We appreciate the contribution of phytochemicals in the treatment of diabetes. Yet, in vitro and in silico studies are needed to validate the safety and efficacy of the phytochemicals, plus their action mechanisms. Methods: Herein, we tested two phytochemicals, caffeic acid and ferulic acid in vitro and in silico. We shed light on the insulin signaling proteins as plausible therapeutic targets using in silico studies, via AutoDock and SwissADME. Results: Results obtained in vitro indicate that Caffeic Acid (CA) increased GLUT4 translocation at 125μM by 31% in the absence of insulin, and 24.5% in presence of insulin, when compared to the control. Ferulic Acid (FA) was less potent as an enhancer of GLUT4 translocation. Best docking results were found for the binding of the phytochemicals CA and FA to PDK1, AKT, IRS1 and PTEN proteins of the insulin signaling, with comparable results. Conclusion: These findings indicate that CA and FA possess a limited anti-diabetic potency by increasing GLUT4 trafficking to the PM in skeletal muscles. These results suggest that these compounds are candidates for further investigation in pre-clinical and clinical stages of drug discovery.

Glucose Transporter 1 Inhibitors Induce Autophagy and Synergize With Lenvatinib in Thyroid Cancer Cells.

Less differentiated thyroid cancer may upregulate the expression of glucose transporter 1 (GLUT1) and increase glycolytic activity. However, it is uncertain whether GLUT1 can be used as a target for therapy. Thyroid cancer cell lines were treated with two different GLUT1 inhibitors, STF-31 and BAY-876. Functional assays were conducted to evaluate the effects of these inhibitors on cell biology. GLUT1 inhibitors dose-dependently decreased cell growth and clonogenicity of thyroid cancer cells. Cell cycle analysis showed that these inhibitors caused G2/M arrest instead of apoptosis. Additionally, treatment with GLUT1 inhibitors led to the activation of autophagy. In both the Transwell and spheroid models, GLUT1 inhibitors significantly suppressed cell invasiveness. Moreover, GLUT1 inhibitors demonstrated synergistic interactions when combined with lenvatinib. Treatment with GLUT1 inhibitors activates autophagy and provokes cell cycle arrest, accompanied by a decrease in colony formation and invasive capacity in thyroid cancer cells.

Dietary thiamine enhances thiamine transport, carbohydrate absorption, glycolysis, and antioxidant properties in Macrobrachium nipponense when fed a high-carbohydrate diet

Thiamine serves as a cofactor of key enzymes involved in glucose metabolism, and its regulatory role in high-carbohydrate diet has not been reported in crustaceans. In this study, six types of isonitrogen and isolipid diets were formulated at two carbohydrate levels (15 % corn starch for the low-carbohydrate group; 30 % corn starch for the high-carbohydrate group) and three concentrations of thiamine (0, 80 and 160 mg/kg) in Macrobrachium nipponense. The carbohydrate metabolism, antioxidant status, and mRNA expression of genes involved in thiamine transport and autophagy of prawns were investigated. The high-carbohydrate diet supplemented with 160 mg/kg thiamine increased the thiamine transporter 1 (SLC19A2) expression compared to a low-carbohydrate diet or other thiamine concentrations. Supplementation with 160 mg/kg thiamine under a high carbohydrate level significantly increased the pyruvate and lactate content in the hepatopancreas. When supplemented with either 0 or 160 mg/kg thiamine, a high dietary carbohydrate significantly increased glucose transporter 4 (GLUT4) and hexokinase (HK) mRNA expressions compared to a low-carbohydrate diet. Among the high-carbohydrate groups, prawns fed with 160 mg/kg thiamine showed significantly higher mRNA expression of pyruvate dehydrogenase-E1-α (PDH-E1-α) compared to those fed with 0 mg/kg thiamine. The activity of superoxide dismutase (SOD) was found to be highest in prawns fed 160 mg/kg thiamine. Supplementation of the carbohydrate diet with either 80 or 160 mg/kg thiamine led to a significant decrease in malondialdehyde (MDA) content accompanied by a significant decrease in glutathione (GSH) level, regardless of low or high carbohydrate levels. The unc-51 like autophagy activating kinase 1 (ULK1) mRNA expression was markedly influenced by both carbohydrate levels and thiamine concentration. Hence, the administration of 160 mg/kg thiamine can improve the thiamine transport, carbohydrate absorption, glycolysis and the antioxidant properties of M. nipponense when fed a high-carbohydrate diet.

Development of a Competitive Nutrient-Based T-Cell Immunotherapy Designed to Block the Adaptive Warburg Effect in Acute Myeloid Leukemia.

Background: T-cell-based adoptive cell therapies have emerged at the forefront of cancer immunotherapies; however, failed long-term survival and inevitable exhaustion of transplanted T lymphocytes in vivo limits clinical efficacy. Leukemia blasts possess enhanced glycolysis (Warburg effect), exploiting their microenvironment to deprive nutrients (e.g., glucose) from T cells, leading to T-cell dysfunction and leukemia progression. Methods: Thus, we explored whether genetic reprogramming of T-cell metabolism could improve their survival and empower T cells with a competitive glucose-uptake advantage against blasts and inhibit their uncontrolled proliferation. Results: Here, we discovered that high-glucose concentration reduced the T-cell expression of glucose transporter GLUT1 (SLC2A1) and TFAM (mitochondrion transcription factor A), an essential transcriptional regulator of mitochondrial biogenesis, leading to their impaired expansion ex vivo. To overcome the glucose-induced genetic deficiency in metabolism, we engineered T cells with lentiviral overexpression of SLC2A1 and/or TFAM transgene. Multi-omics analyses revealed that metabolic reprogramming promoted T-cell proliferation by increasing IL-2 release and reducing exhaustion. Moreover, the engineered T cells competitively deprived glucose from allogenic blasts and lessened leukemia burden in vitro. Conclusions: Our findings propose a novel T-cell immunotherapy that utilizes a dual strategy of starving blasts and cytotoxicity for preventing uncontrolled leukemia proliferation.

Active transport conceptual assessment (ATCA): a new tool for supporting the teaching and learning of physiology

ABSTRACT The physiological processes involved in the movement of molecules across a cell membrane form the basis for understanding several core concepts of physiology. A 10-item, two-tier multiple-choice diagnostic test was developed to evaluate first-year physiology students’ knowledge of active transport across the cell membrane. The diagnostic test was developed by collating common mistakes and areas of troublesome knowledge from tutorial worksheets, academic discussions, and the literature. A list of propositional statements was constructed, and questions were developed from these statements. The test was further refined following dialogue with students and physiology teaching staff. Analysis of the responses from two cohorts of first-year Human Physiology students (n = 886) demonstrated the assessment had a wide range of difficulty and good discrimination. Students performed better on the tier-one questions (What?) compared to the tier 2 questions (Why?). Several misconceptions were identified around the transport of glucose across the membrane, the predominant ions in the extracellular and intracellular fluids, and the role of ATP in active membrane transport. This diagnostic information can be used as a learning tool for students as a self-testing strategy, and for teachers as a method to evaluate and modify teaching practices.

Vitamin D3 mitigates myopathy and metabolic dysfunction in rats with metabolic syndrome: the potential role of dipeptidyl peptidase-4.

Metabolic syndrome is associated with vitamin D3 deficiency. This work aims to examine the efficacy of vitamin D3 in inhibiting MetS-induced myopathy and to determine whether the beneficial effects of vitamin D3 are mediated by the inhibition of dipeptidyl peptidase-4 (DPP-4). An in silico study investigated the potential effectiveness of vitamin D3 on the inhibition of the DPP-4 enzyme. An in vitro assay of the DPP-4 inhibitory effect of vitamin D3 was performed. In vivo and over 12 weeks, both diet (with 3% salt) and drinking water (with 10% fructose) were utilized to induce MetS. In the seventh week, rats received either vitamin D3, vildagliptin, a combination of both, or vehicles. Serum lipids, adipokines, glycemic indices, and glucagon-like peptide-1 (GLP-1), muscular glucose transporter type-4 (GLUT-4) content, DPP-4, adenosine monophosphate kinase (AMPK) activities, and Sudan Black B-stained lipids were assessed. Muscular reactive oxygen species (ROS), caspase-3, and desmin immunostaining were used to determine myopathy. MetS-induced metabolic dysfunction was ameliorated by vitamin D3, which also reduced intramuscular glycogen and lipid accumulation. This is demonstrated by the attenuation of MetS-induced myopathy by vitamin D3, decreased oxidative stress, increased desmin immuno-expression, and caspase-3 activity. Our in silico data demonstrated that vitamin D3 is capable of inhibiting DPP-4, which is further supported by biochemical findings. Vitamin D3 increased serum GLP-1, muscular AMPK activity, and GLUT-4 content, whereas the levels of muscular ROS were decreased in MetS. Vildagliptin and its combination with vitamin D3 yielded comparable results. It is suggested that the DPP-4 inhibitory potential of vitamin D3 is responsible for the amelioration of MetS-induced metabolic changes and myopathy.

CRISPR–Cas9 screens reveal regulators of ageing in neural stem cells

Ageing impairs the ability of neural stem cells (NSCs) to transition from quiescence to proliferation in the adult mammalian brain. Functional decline of NSCs results in the decreased production of new neurons and defective regeneration following injury during ageing1–4. Several genetic interventions have been found to ameliorate old brain function5–8, but systematic functional testing of genes in old NSCs—and more generally in old cells—has not been done. Here we develop in vitro and in vivo high-throughput CRISPR–Cas9 screening platforms to systematically uncover gene knockouts that boost NSC activation in old mice. Our genome-wide screens in primary cultures of young and old NSCs uncovered more than 300 gene knockouts that specifically restore the activation of old NSCs. The top gene knockouts are involved in cilium organization and glucose import. We also establish a scalable CRISPR–Cas9 screening platform in vivo, which identified 24 gene knockouts that boost NSC activation and the production of new neurons in old brains. Notably, the knockout of Slc2a4, which encodes the GLUT4 glucose transporter, is a top intervention that improves the function of old NSCs. Glucose uptake increases in NSCs during ageing, and transient glucose starvation restores the ability of old NSCs to activate. Thus, an increase in glucose uptake may contribute to the decline in NSC activation with age. Our work provides scalable platforms to systematically identify genetic interventions that boost the function of old NSCs, including in vivo, with important implications for countering regenerative decline during ageing.

Short term sodium glucose transport protein 2 inhibitors are associated with post contrast acute kidney injury in patients with diabetes

Although sodium–glucose transport protein-2 (SGLT2) inhibitors (SGLT2i) do not increase the risk of acute kidney injury (AKI) in general, they may pose a risk in patients undergoing angiography. This prospective cohort study aimed to evaluate the safety and efficacy of SGLT2i for post-contrast AKI (PC-AKI) in patients with type 2 diabetes mellitus (T2DM). Following screening, 306 patients with T2DM selected to undergo coronary arterial angiography with or without percutaneous intervention were enrolled. Patients were divided into the SGLT2i exposure and non-exposure groups. The primary outcome was PC-AKI, defined as an increase in serum creatinine levels > 0.5 mg/dL (44.2 µmol/L), or 25% above the baseline, within 48–72 h after exposure to contrast medium. The incidence of PC-AKI in the overall T2DM population was 5.2% (16/306). Following 1:1 propensity score matching, the incidence of PC-AKI was significantly higher in the SGLT2i group than in the non-SGLT2i group (10.7% vs. 2.9%; P = 0.027), with an odds ratio of 4.5 (95% confidence interval: 1.0–20.2; P = 0.047). Furthermore, PC-AKI occurred at a higher rate among short-term users of SGLT2i than long-term users (20.5% vs. 3.4%, P = 0.018). Thus, our findings suggest an increased risk of PC-AKI associated with short-term SGLT2i therapy in patients with T2DM.

Downregulation of glucose-energy metabolism via AMPK signaling pathway in granulosa cells of diminished ovarian reserve patients

Glucose metabolism plays a crucial role in the function of granulosa cells (GCs) and the development of follicles. In cases of diminished ovarian reserve (DOR), alterations in these processes can impact female fertility. This study aims to investigate changes in glucose-energy metabolism in GCs of young DOR patients aged 20 to 35 years and their correlation with the onset and progression of DOR. 72 DOR cases and 75 women with normal ovarian reserve (NOR) as controls were included based on the POSEIDON and Bologna criteria. Samples of GCs and follicular fluid (FF) were collected for a comprehensive analysis involving transcriptomics, metabolomics, RT-qPCR, JC-1 staining, and flow cytometry. The study identified differentially expressed genes and metabolites in GCs of DOR and NOR groups, revealing 7 common pathways related to glucose-energy metabolism, along with 11 downregulated genes and 14 metabolites. Key substances in the glucose-energy metabolism pathway, such as succinate, lactate, NADP, ATP, and ADP, showed decreased levels, with the DOR group exhibiting a reduced ADP/ATP ratio. Downregulation of genes involved in glycolysis (HK, PGK, LDH1), the TCA cycle (CS), and gluconeogenesis (PCK) was observed, along with reduced glucose content and expression of glucose transporter genes (GLUT1 and GLUT3) in DOR GCs. Additionally, decreased AMPK pathway activity and impaired mitochondrial function in DOR suggest a connection between mitochondrial dysfunction and disrupted energy metabolism. Above all, the decline in glucose-energy metabolism in DOR is closely associated with its onset and progression. Reduced glucose uptake and impaired mitochondrial function in DOR GCs lead to internal energy imbalances, hindering the AMPK signaling pathway, limiting energy production and supply, and ultimately impacting follicle development and maturation.

2-Hydroxylation is a chemical switch linking fatty acids to glucose-stimulated insulin secretion

Glucose-stimulated insulin secretion (GSIS) in pancreatic β-cells is metabolically regulated and progressively diminished during the development of type 2 diabetes (T2D). This dynamic process is tightly coupled with fatty acid metabolism, but the underlying mechanisms remain poorly understood. Fatty acid 2-hydroxylase (FA2H) catalyzes the conversion of fatty acids to chiral specific (R)-2-hydroxy fatty acids ((R)-2-OHFAs), which influences cell metabolism. However, little is known about its potential coupling with GSIS in pancreatic β cells. Here, we showed that Fa2h knockout decreases plasma membrane localization and protein level of glucose transporter 2 (GLUT2), which is essential for GSIS, thereby controlling blood glucose homeostasis. Conversely, FA2H overexpression increases GLUT2 on the plasma membrane and enhances GSIS. Mechanistically, FA2H suppresses the internalization and trafficking of GLUT2 to the lysosomes for degradation. Overexpression of wild-type FA2H, but not its mutant with impaired hydroxylase activity in the pancreatic β-cells, improves glucose tolerance by promoting insulin secretion. Levels of 2-OHFAs and Fa2h gene expression are lower in high-fat diet-induced obese mouse islets with impaired GSIS. Moreover, lower gene expression of FA2H is observed in a set of human T2D islets when the insulin secretion index is significantly suppressed, indicating the potential involvement of FA2H in regulating mouse and human GSIS. Collectively, our results identified an FA chemical switch to maintain the proper response of GSIS in pancreatic β cells and provided a new perspective on the β-cell failure that triggers T2D.

Generation of human induced pluripotent stem cell lines derived from two glucose transporter 1 deficiency syndrome patients

Glucose transporter 1 deficiency syndrome (GLUT1DS), caused by impaired glucose transport at the blood–brain barriers, leads to various central nervous system dysfunctions. A comprehensive understanding of the underlying disease pathogenesis is still lacking. In this study, we have generated GLUT1DS-specific human induced pluripotent stem cells (hiPSCs) derived from two patients. These established GLUT1DS-specific hiPSC lines showed self-renewal and pluripotency and carried heterozygous frameshift or missense mutations in the responsible SLC2A1 gene. These novel cell resources provide new avenues for understanding disease mechanisms and developing new therapies for GLUT1DS

Withanolides-enriched leaf extract of Withania somnifera exert anti-obesity effects by inducing brown adipocyte-like phenotype via tuning MAP-kinase signaling axis

Present study investigated anti-obesity potential of Withania somnifera (L.) Dunal leaf extract (WSLE). Phytochemical characterization of WSLE was performed by UPLC/MS-QToF and HPLC-based analysis. WSLE was assessed for its effect on lipid metabolism and mitochondrial biogenesis in vitro using differentiated 3 T3-L1 adipocytes. WSLE was found to contain 59 phytometabolites with a total of 10.601 μg withanolides per mg of extract. WSLE (30 μg/ml) treatment decreased basal levels of intracellular lipids and triglycerides to 13.85 % and 41.58 %, respectively. WSLE downregulated the expression of PPARγ, C/EBPα, C/EBPβ, and their target genes responsible for lipogenesis dose-dependently. An upregulation in expression of lipolytic (ATGL and HSL), thermogenic (PGC1α, UCP1, and PRDM16), and glucose transporter (GLUT4) genes was also observed. Furthermore, WSLE treatment increased glucose uptake by 1.5-fold. These beneficial effects of WSLE were abolished in presence of AMPK, p38MAPK, and ERK inhibitors. These observations were then validated in vivo using Caenorhabditis elegans as a model organism. Intriguingly, WSLE diminished fat accumulation in wild-type N2 worms as evident from reduced Oil-red-O staining and reduction in GFP expression of fat-5, 6, and 7 in transgenic strains. Overall, these results highlight anti-obesity potential of WSLE exerting its effects via alterations in AMPK/p38MAPK/ERK axis.

Ziziphus jujuba (Jujube) in Metabolic Syndrome: From Traditional Medicine to Scientific Validation.

This review evaluates the therapeutic potential of Ziziphus jujuba and its main components in managing complications of metabolic syndrome, including diabetes, dyslipidemia, obesity, and hypertension. The reviewed studies provide evidence supporting the use of Z. jujuba and its main components (lupeol and betulinic acid) as natural treatments for complications of metabolic syndrome. These substances enhance glucose uptake through the activation of signaling pathways such as phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt), reduce hepatic glucose synthesis, and increase glucose uptake by adipocytes and skeletal muscle cells. They also improve insulin sensitivity by modulating AMP-activated protein kinase (AMPK) activity and regulating insulin signaling proteins and glucose transporters. In the field of dyslipidemia, they inhibit triglyceride synthesis, lipid accumulation, and adipogenic enzymes, while influencing key signaling pathways involved in adipogenesis. Z. jujuba and its constituents demonstrate anti-adipogenic effects, inhibiting lipid accumulation and modulating adipogenic enzymes and transcription factors. They also exhibit positive effects on endothelial function and vascular health by enhancing endothelial nitric oxide synthase (eNOS) expression, NO production, and antioxidant enzyme activity. Z. jujuba, lupeol, and betulinic acid hold promise as natural treatments for complications of metabolic syndrome. They improve glucose metabolism, insulin sensitivity, and lipid profiles while exerting anti-adipogenic effects and enhancing endothelial function. However, further research is needed to elucidate the mechanisms and confirm their efficacy in clinical trials. These natural compounds offer potential as alternative therapies for metabolic disorders and contribute to the growing body of evidence supporting the use of natural medicines in their management.