GLUT4 Protein Expression Research Articles

FOSL2 activates TGF-β1-mediated GLUT1/mTOR signaling to promote diabetic kidney disease.

Diabetic kidney disease (DKD) is a major cause of kidney failure. FOS-like antigen 2 (FOSL2) has been revealed to be increased in kidney biopsies of patients with lupus nephritis, while its association with DKD remains unsolved. This study aimed to characterize the role of FOSL2 in DKD and its mechanism. The kidney tissues of DKD mice induced by STZ and a high-fat diet were subjected to PAS and Masson's staining. Glomerular mesangial cells (MCs) were treated with high glucose (HG) or normal glucose (NG). CCK-8 and EdU assays were performed to detect cell proliferation, and immunoblotting was conducted to analyze ECM deposition. ChIP-qPCR was performed on MCs to detect the binding of FOSL2 on the TGF-β1 promoter and a dual-luciferase assay to detect the impact of FOSL2 on the transcription of the TGF-β1 promoter. FOSL2 was elevated in the kidney tissues of DKD mice. Knockdown of FOSL2 reduced the mRNA expression of TGF-β1 to decrease the protein expression of GLUT1 and mTOR in the kidney tissues of DKD mice, and TGF-β1 reversed the effects caused by knockdown of FOSL2. The mTOR inhibitor Rapamycin alleviated kidney injury in the presence of FOSL2. Knockdown of FOSL2 inhibited the proliferation and improved ECM deposition of MCs, which were reversed by TGF-β1. Rapamycin and GLUT1 inhibitor BAY-876 reversed the promotion effect of FOSL2 on the proliferation of NG-MCs/HG-MCs and improved ECM deposition of MCs. Our data demonstrated that FOSL2 accentuates DKD in mice by increasing TGF-β1-induced GLUT1/mTOR signaling.

A novel approach to regulate glucose uptake in an anaplastic thyroid cancer cell line.

Curcumin's function in affecting cancer metabolic reprogramming remains poorly understood. Herein, we aimed to elucidate a novel link between Curcumin and the glucose uptake metabolism and glucose transporters (GLUTs) status in SW1736 cell line derived from anaplastic thyroid cancer. TheMTT test and flow cytometry was employed to test cell viability and cell death. For glucose uptake detection, ''GOD-PAP'' enzymatic colorimetric assay was applied to measure the direct glucose levels inside of the cells. Determination of GLUT1 and GLUT3 mRNA and protein expression in SW1736 cells was performed by qRT-PCR and western blotting. Also, the scratch wound healing assay was conducted for cell migration. The data indicated that Curcumin-induced cell death is independent of apoptosis in this type of thyroid cancer cell line. Furthermore, significantly reduced GLUT1 and GLUT3 expression was observed after treatment with Curcumin, resulting in the inhibition of glucose uptake (p < 0.05). Scratch assay indicated the inhibition of cell migration in SW1736 cells treated by Curcumin (p < 0.05). It can be concluded that GLUTs as metabolic targets can be blocked specifically by Curcumin for thyroid cancer prevention. Curcumin, as a promising anti-cancer agent, inhibits the growth of SW1736 anaplastic thyroid cancer cell line by regulating glucose uptake pathway and cell death. Altogether, these results suggest that the glucose pathway may be an important target for therapeutic intervention to sensitize tumor cells to cell death process by inhibition of glucose transporters.

Reduction of hyperglycemia in STZ-induced diabetic mice by prophylactic treatment with heat-killed Mycobacterium aurum: possible effects on glucose utilization, mitochondrial uncoupling, and oxidative stress in liver and skeletal muscle.

In addition to conventional treatment and modifications in physical activity and diet, alternative strategies have been investigated to manage, prevent, or delay diabetes in humans. In this regard, one strategy has relied on the immunomodulatory properties of mycobacteria, whereby Bacillus Calmette-Guerin, an attenuated live strain of Mycobacterium bovis, has been shown to improve glycemic control in patients with diabetes and to alleviate hyperglycemia in selected murine models of diabetes. A novel heat-killed (HK) whole-cell preparation of Mycobacterium aurum (M. aurum) is currently under development as a potential food supplement; nevertheless, its potential bioactivity remains largely unknown. Thus, the present study investigated the potential prophylactic anti-diabetic effects of HK M. aurum in streptozotocin (STZ)-induced diabetic mice. Mice were divided into three groups: the STZ-induced diabetic group was injected with a single intraperitoneal high dose of STZ, the HK M. aurum-treated diabetic group was prophylactically treated with three doses of HK M. aurum 6 weeks before STZ injection, and the control non-diabetic group was given three intradermal injections of borate-buffered saline and an intraperitoneal injection of citrate buffer. Liver lactate dehydrogenase (LDH), uncoupling protein 2 (UCP2), and glucose transporter 2 (GLUT2) and skeletal muscle LDH, UCP3, and GLUT4 protein expression levels in different mouse groups were determined by Western blot. Our results indicated that HK M. aurum did not cause any significant changes in glycemic levels of normal non-diabetic mice. Prophylactic administration of three doses of HK M. aurum to diabetic mice resulted in a significant reduction in their blood glucose levels when compared to those in control diabetic mice. Prophylactic treatment of diabetic mice with HK M. aurum significantly restored their disturbed protein expression levels of liver UCP2 and LDH as well as of skeletal muscle UCP3. On the other hand, prophylactic treatment of diabetic mice with HK M. aurum had no significant effect on their liver GLUT2 and skeletal muscle GLUT4 and LDH protein expression levels. Our findings provide the first evidence that HK M. aurum possesses a hyperglycemia-lowering capacity and might support its future use as a food supplement for the amelioration of diabetes.

Quercetin slow-release system delays starch digestion via inhibiting transporters and enzymes

This study investigates the potential of a quercetin-based emulsion system to moderate starch digestion and manage blood glucose levels, addressing the lack of in vivo research. By enhancing quercetin bioaccessibility and targeting release in the small intestine, the emulsion system demonstrates significant inhibition of starch digestion and glucose spikes through both in vitro and in vivo experiments. The system inhibits α-amylase and α-glucosidase via competitive and mixed inhibition mechanisms, primarily involving hydrogen bonds and van der Waals forces, leading to static fluorescence quenching. Additionally, this system downregulates the protein expression and gene transcription of SGLT1 and GLUT2. These findings offer a novel approach to sustaining glucose equilibrium, providing a valuable foundation for further application of quercetin emulsion in food science.

Exploring the Anticancer Potential of Astragalin in Triple Negative Breast Cancer Cells by Attenuating Glycolytic Pathway through AMPK/mTOR.

Aerobic glycolysis is crucial for cancer cells to survive, grow, and progress. In the current study, the anti-cancer effects of astragalin (ASG) on breast cancer cells and in the glycolytic pathway through AMPK/mTOR have been evaluated. The objective of this study was to examine the impact of ASG, a natural flavonoid, on glycolysis via targeting AMPK/mTOR signalling in MDA-MB-231 breast cancer cells. The study utilized ASG, which was isolated from Haplophyllum tuberculatum. The cells were treated with different concentrations of ASG (20 and 40 μg/mL), and anti- glycolytic activities were measured through cell proliferation, expression of glycolytic enzymes (HK-2, LDH-A, GLUT-1), glucose uptake, and lactate concentration assays. The MTT assay was used to assess cellular proliferation, while the glucose uptake and lactate levels were determined by employing colorimetric assays. The mRNA expression of target glycolytic enzymes was determined by qRT-PCR. The protein levels of glycolytic targets, as well as that of AMPK and mTOR, were determined by western blot. in silico docking of ASG was done with mTOR and AMPK proteins. Astragalin exhibited dose- and time-dependent anti-proliferative effects in MDA-MB-231 cells. In breast cancer cells, the mRNA and protein expression of GLUT-1, LDH-A, and HK-2 were all significantly downregulated after receiving ASG treatments. Furthermore, after ASG treatments, MDA-MB231 cells showed a significant decrease in lactate and glucose uptake compared to control cells. Mechanistically, ASG increased AMPK activation and suppressed mTOR activation in these cells. The inhibitory role of ASG on aerobic glycolysis was prevented by treatments with compound C (an AMPK inhibitor). However, combined treatment of compound C and ASG could nullify the ASG-induced anti-glycolysis effect and restore the level of p-AMPK and p-mTOR in MDA-MB231 cells. The results from molecular docking predicted that ASG had the potential to bind AMPK and mTOR, with free energy for binding, -8.2 kcal/mol and -8.1 kcal/mol, respectively. Taken together, the findings from this study indicated that ASG might modulate the AMPK/mTOR pathway to inhibit aerobic glycolysis and proliferation of MDAMB231 breast cancer.

Moderate aerobic training enhances the effectiveness of insulin therapy through hypothalamic IGF1 signaling in rat model of Alzheimer's disease

Alzheimer's disease (AD) is a neurological condition that is connected with a decline in a person's memory as well as their cognitive ability. One of the key topics of AD research has been the exploration of metabolic causes. We investigated the effects of treadmill exercise and intranasal insulin on learning and memory impairment and the expression of IGF1, BDNF, and GLUT4 in hypothalamus. The animals were put into 9 groups at random. In this study, we examined the impact of insulin on spatial memory in male Wistar rats and analyzed the effects of a 4-week pretreatment of moderate treadmill exercise and insulin on the mechanisms of improved hypothalamic glucose metabolism through changes in gene and protein expression of IGF1, BDNF, and GLUT4. We discovered that rat given Aβ25–35 had impaired spatial learning and memory, which was accompanied by higher levels of Aβ plaque burden in the hippocampus and lower levels of IGF1, BDNF, and GLUT4 mRNA and protein expression in the hypothalamus. Additionally, the administration of exercise training and intranasal insulin results in the enhancement of spatial learning and memory impairments, the reduction of plaque burden in the hippocampus, and the enhancement of the expression of IGF1, BDNF, and GLUT4 in the hypothalamus of rats that were treated with Aβ25–35. Our results show that the improvement of learning and spatial memory due to the improvement of metabolism and upregulation of the IGF1, BDNF, and GLUT4 pathways can be affected by pretreatment exercise and intranasal insulin.

Thyroid-stimulating hormone induces insulin resistance in adipocytes via endoplasmic reticulum stress.

Subclinical hypothyroidism (SCH) is closely related to insulin resistance, and thyroid-stimulating hormone (TSH) level is an independent factor for insulin resistance associated with subclinical hypothyroidism. This study aims to explore the effects of TSH levels on insulin signal transduction in adipocytes and to establish the role of endoplasmic reticulum (ER) stress in this process. In this study, the SCH mouse model was established, and 3T3-L1 adipocytes were treated with TSH or tunicamycin (TM), with or without 4-phenylbutyric acid (4-PBA), an inhibitor of ER stress. Subclinical hypothyroidism mice exhibited impaired glucose tolerance, inactivation of the IRS-1/AKT pathway, and activation of the IRE1/JNK pathway in adipose tissue, which can all be alleviated by 4-PBA. Supplementation with levothyroxine restored the TSH to normal, alongside alleviated ER stress and insulin resistance in SCH mice, which is characterized by improved glucose tolerance, decreased mRNA expression of IRE1, and decreased phosphorylation of JNK in adipose tissue. In 3T3-L1 adipocytes, TSH induces insulin resistance, leading to a decrease in glucose uptake. This effect is mediated by the downregulation of IRS-1 tyrosine phosphorylation, reduced AKT phosphorylation, and inhibited GLUT4 protein expression. Notably, all these effects can be effectively reversed by 4-PBA. Moreover, TSH induced TNF-α and IL-6 production and upregulated the expression of ER stress markers. Similarly, these changes can be recovered by 4-PBA. These findings indicate that TSH has the capability to induce insulin resistance in adipocytes. The mechanism through which TSH disrupts insulin signal transduction appears to involve the ER stress-JNK pathway.

HGG-05. GLUCOSE CONJUGATION FOR THE SPECIFIC TARGETING AND TREATMENT OF GLIOBLASTOMA

Abstract BACKGROUND Malignant brain tumors, such as Glioblastoma (GBM), are a major challenge in oncology with a dismal prognosis. This can be in part explained by the inability to deliver more effective drugs, as Doxorubicin (DOX), into the brain because of resistance mechanisms. Malignant tumors as GBM also show an elevated glycolytic rate through glucose transporters and GLUT1 is reported to be the main mediator of BBB glucose uptake. For these reasons, we have developed an innovative approach able to increase drug efficiency and selectivity, by conjugating the anticancer agents DOX to glucose. METHODS Two glycoconjugates (EB73 and EB74) were synthesized, using an oxime-based linkers between position 6 of glucose and carbonyl group of DOX, and characterized for absorbance, fluorescence and binding affinity to ctDNA. The cytotoxic effect of EB73 and EB74 was evaluated in two GBM cell lines (A172 and T98G). These cells were also used to study the effect of glucose deprivation on GLUT1 and breast cancer resistance protein (BCRP) expression. Moreover, cellular uptake of the glicoconjugates was evaluate in an in vitro BBB model and by immunofluorescence (IF) in GBM cells. RESULTS Our results indicated that EB73 and EB74 maintained Ka binding constants comparable to DOX, confirming that functionalization with glucose did not alter DOX intercalation capability and fluorescence. The cytotoxicity results demonstrated that EB74 has the major effect in A172 and T98G DOX-resistant cells starting from 24h of treatment. Moreover, glucose deprivation showed a GLUT1 overexpression and BCRP downregulation in both cell lines improving EB74 efficacy. BBB in vitro model and IF experiments revealed that only EB74 is able to accumulate in cells nuclei as conventional DOX CONCLUSION In conclusion, these results indicated that glycoconjugation of DOX and glucose deprivation may be helpful instruments to increase drugs uptake and effectiveness in aggressive and chemoresistant tumor cells.

Aspartate-β-hydroxylase and hypoxia marker expression in head and neck carcinomas: implications for HPV-associated tumors

BackgroundA proportion of head and neck carcinomas (HNSCCs) are induced by high-risk human papillomaviruses (HPVs) and are associated with better patient outcomes compared to patients with HNSCCs related to tobacco and alcohol abuse. In the microenvironment of solid tumors, including HNSCCs, oxygen levels are often reduced, and a hypoxic state is induced. This can lead to a poor treatment response and a worse patient prognosis. One of the hypoxia-responsive genes is aspartate-β-hydroxylase (ASPH), whose activity promotes the growth, invasiveness, and metastasis of many types of solid tumors.MethodsIn our study, HNSCC samples were analyzed for the expression of ASPH and selected endogenous hypoxia markers by real-time PCR and/or multiplex fluorescence immunohistochemistry.ResultsExcept for the EPAS1 gene, which had higher mRNA expression in the HPV-negative group of HNSCC (p < 0.05), we found no other differences in the expression of the tested genes that were related to HPV status. On the contrary, a statistically significantly higher number of cells producing ASPH (p < 0.0001), HIF1A (p < 0.0001), GLUT1 (p < 0.0001), and MMP13 (p < 0.05) proteins were detected in the HPV-positive tumor group than in the HPV-negative sample group. All the evaluated markers, except for MMP9/13, were more abundant in the tumor parenchyma than in the tumor stroma. The Cox proportional hazard models showed that increased numbers of cells with GLUT1 and HIF1A protein expression were positive prognostic markers for overall and disease-specific survival in patients independent of HPV tumor status.ConclusionThe study examined HNSCC samples and found that elevated ASPH and hypoxia marker proteins, typically associated with poor prognosis, may actually indicate active HPV infection, the strongest prognostic factor in HNSCC patients. In cases where HPV status is uncertain, increased expression of HIF1A and GLUT1 can serve as positive prognostic factors.

Effects of asiaticoside on the model of gestational diabetes mellitus in HTR-8/svneo cells via PI3K/AKT pathway

Background Asiaticoside (AS) has been reported to improve the changes induced by high glucose stimulation, and it may have potential therapeutic effects on gestational diabetes mellitus (GDM). This study aims to explore the effect of AS on the cell model of GDM and the action mechanism of the PI3K/AKT pathway. Methods The GDM model was established in HTR-8/Svneo cells with a high glucose (HG) medium. After the cytotoxicity assay of AS, cells were divided into the control group, HG group and HG + AS group to conduct control experiment in cells. The cell proliferation and migration were detected by CCK-8 assay and scratch test, respectively. The mRNA levels of PI3K, AKT2, mTORC1, and GLUT4 in PI3K/AKT signalling pathway were measured by RT-PCR, and the protein expressions of these signalling molecules were monitored by western blot. Results AS showed a promotion effect on the cell proliferation rate of HTR-8/Svneo cells, and 80 μmol/L AS with a treatment time of 48 h had no cytotoxicity. The cell proliferation rate, migration rate, mRNA levels and protein expressions of PI3K, AKT2, mTORC1, and GLUT4 in the HG group were significantly lower than those in the control group, which were significantly increased in the HG + AS group (p < 0.05). Conclusions AS can facilitate the cell proliferation and migration in the cell model of GDM, and might play a role in GDM treatment via PI3K/AKT pathway.

L-arginine combination with 5-fluorouracil inhibit hepatocellular carcinoma cells through suppressing iNOS/NO/AKT-mediated glycolysis.

L-arginine can produce nitric oxide (NO) under the action of inducible nitric oxide synthase (iNOS), while 5-fluorouracil (5-FU) can induce the increase of iNOS expression. The present study was to investigate the mechanism of L-arginine combined with 5-FU regulating glucose metabolism of hepatocellular carcinoma (HCC) through iNOS/NO/AKT pathway. The combination of L-arginine and 5-FU resulted in decreased cell survival and exhibited synergistic cytotoxic effects in HepG2 and SMMC7721 cells. Meanwhile, L-arginine increased 5-FU inhibitory effect on HepG2 and SMMC7721 cells by increasing NO production. Co-treatment with L-arginine and 5-FU resulted in a significant decrease in both G6PDH and LDH enzymatic activities, as well as reduced levels of ATP and LD compared to treatment with L-arginine or 5-FU alone. Moreover, the combination of L-arginine and 5-FU resulted in a decrease in the expression of GLUT1, PKM2, LDHA, p-PI3K and p-AKT. Furthermore, the combination demonstrated a synergistic effect in downregulating the expression of HIF-1α and β-catenin, which were further diminished upon the addition of shikonin, a specific inhibitor of PKM2. LY294002 treatment further reduced the expression of GLUT1, PKM2, and LDHA proteins induced by combined L-arginine and 5-FU treatment compared to the combined group. However, the reduction in p-PI3K, p-AKT, and GLUT1 expression caused by L-arginine and 5-FU combination was also reversed in HepG2 and SMMC7721 cells with iNOS knockdown, respectively. Additionally, the combination of L-arginine and 5-FU led to a greater reduction in the enzymatic activity of ALT, AST, G6PDH and LDH, as well as a significant reduction in hepatic index, AFP, AFP-L3, ATP and LD levels in a rat model of HCC. Moreover, the simultaneous administration of L-arginine and 5-FU significantly improved the gross morphology of the liver, reduced nuclear atypia, inhibited the proliferation of cancer cells, and decreased the expression levels of p-PI3K, p-AKT, GLUT1, PKM2, and LDHA, while iNOS expression was increased in the combination group. Taking together, L-arginine and 5-FU combination resulted in the inhibition of enzymes in aerobic glycolysis via the iNOS/NO/AKT pathway, which led to the suppression of glucose metabolism and downregulation of nuclear transcription factors, thereby impeding the proliferation of hepatocellular carcinoma cells.

Regulation and Role of Adiponectin Secretion in Rat Ovarian Granulosa Cells.

Adiponectin is an important adipokine involved in glucose and lipid metabolism, but its secretion and potential role in regulating glucose utilization during ovarian development remains unclear. This study aims to investigate the mechanism and effects of follicle-stimulating hormones (FSHs) on adiponectin secretion and its following impact on glucose transport in the granulosa cells of rat ovaries. A range of experimental techniques were utilized to test our research, including immunoblotting, immunohistochemistry, immunofluorescence, ELISA, histological staining, real-time quantitative PCR, and transcriptome analysis. The immunohistochemistry results indicated that adiponectin was primarily located in the granulosa cells of rat ovaries. In primary granulosa cells cultured in vitro, both Western blot and immunofluorescence assays demonstrated that FSH significantly induced adiponectin secretion within 2 h of incubation, primarily via the PKA signaling pathway rather than the PI3K/AKT pathway. Concurrently, the addition of the AdipoR1/AdipoR2 dual agonist AdipoRon to the culture medium significantly stimulated the protein expression of GLUT1 in rat granulosa cells, resulting in enhanced glucose absorption. Consistent with these in vitro findings, rats injected with eCG (which shares structural and functional similarities with FSH) exhibited significantly increased adiponectin levels in both the ovaries and blood. Moreover, there was a notable elevation in mRNA and protein levels of AdipoRs and GLUTs following eCG administration. Transcriptomic analysis further revealed a positive correlation between the expression of the intraovarian adiponectin system and glucose transporter. The present study represents a novel investigation, demonstrating that FSH stimulates adiponectin secretion in ovarian granulosa cells through the PKA signaling pathway. This mechanism potentially influences glucose transport (GLUT1) and utilization within the ovaries.

In Utero Overnutrition Influences Placental Nutrient Transport and Fetal Overgrowth

Obesity is defined as a body mass index (BMI) ≥30 kg/m2. Forty-three percent of women of childbearing age are obese, with a greater prevalence noted in Black women. Obesity increases the risk of diabetes (Type 2 diabetes mellitus (T2DM) and gestational diabetes mellitus (GDM)). Obesity and diabetes are chronic states of overnutrition and metabolic dysregulation, each associated with an increased risk of macrosomia (large weight for gestational age in offspring). Macrosomia not only increases pregnancy complications but also increases the risk of metabolic disorders throughout the lifespan of the offspring. Fetal growth in utero is mediated by the nutritional environment and nutritional transport across the placenta. Maternal-fetal nutrient transport is primarily mediated by placental transporters for glucose, amino acids, free fatty acids, and cholesterol in the syncytiotrophoblast of the placenta. Yet, the mechanistic pathway driving fetal overgrowth in environments of overnutrition are not well defined. Therefore, we will test the hypothesis that diabetes (T2DM or GDM) exacerbates placental nutrient transport and fetal overgrowth in Black pregnant women with obesity. To evaluate the combined influence of obesity and diabetes (T2DM or GDM) on fetal growth, we evaluated n=100 electronic medical records of Black obese women with and without diabetes (T2DM or GDM) from 2012-2022 at the University of Mississippi Medical Center (UMMC). These women were singleton pregnancies with no additional underlying conditions. Gestational age of offspring and maternal age were similar among all groups. This study was approved by the Institutional Review Board at UMMC (IRB-UMMC-2021-0455). We found that Black obese women with diabetes (n=43) had higher BMIs compared to Black women with obesity alone (n=57) (43.50 ± 4.76 kg/m2 vs. 39.19 ± 3.48 kg/m2) (p&lt;0.05), indicating that obesity increases risk of diabetes in Black pregnant women. Additionally, offspring from Black obese women with diabetes had elevated birthweight compared to offspring from women with obesity alone (3345 ± 614.6 g vs. 3099 ± 465.4 g; p&lt;0.05). Male offspring from Black obese women with diabetes had elevated birthweight (3460 ± 695.8 g) compared to female offspring from Black obese women without diabetes (3068 ± 439.8 g) (p&lt;0.05), suggesting the maternal nutritional environment influences males more than females. Yet, the type of diabetes, T2DM or GDM, did not influence birthweight in offspring from Black obese women (T2DM: 3412 ± 743.5 g vs GDM: 3271 ± 439.7 g). To evaluate the influence of obesity plus diabetes on placental nutrient transport, we measured placental protein expression of glucose transporter-1 (Glut-1), a primary glucose transporter in the placenta, in a separate subset of placental tissue from Black obese women with and without diabetes (IRB-UMMC-2019-0058). Protein expression of Glut-1 was increased in placental tissue from Black women with obesity and diabetes (n=4) compared to Black women with obesity alone (n=4) (20.38 ± 5.87 A.U. vs. 9.41 ± 1.46 A.U.; p&lt;0.05). However, BMI was elevated in the group of women with obesity and diabetes compared to obesity alone (49.565 ± 1.39 kg/m2 vs. 43.44 ± 2.44 kg/m2; p&lt;0.05), again indicating that obesity increases risks of diabetes in Black pregnant women. This study indicates that combined obesity with diabetes during pregnancy is associated with increased birthweight and placental protein expression of Glut-1. Additional studies are warranted to decipher the separate influences of elevated BMI and diabetes on fetal growth, along with the associated placental mechanisms that influence nutrient transport and fetal growth in pregnancies complicated by obesity and diabetes. UMMC Department of OBGYN. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Beta cell-derived exosomes from KDM6A KO mice enhances glucose uptake via upregulation of GLUT4 in skeletal muscles and adipocytes

Exosomes are small extracellular vesicles secreted by various cell types which have gained prominence as potent mediators of intercellular communication. Beta cells play a critical role in glucose homeostasis through the production and secretion of insulin. Lysine demethylase 6A (KDM6A) belongs to the KDM6 family of histone H3 lysine 27 (H3K27) demethylases which is important for the development of various organs. Our previous study showed that beta cell-specific knockout of KDM6A increased glucose tolerance and enhanced peripheral insulin sensitivity in mice. The aim of this study is to investigate whether beta cell-derived exosomes, particularly those derived from KDM6A knockout (INS1-KDM6A-KO) beta cells, regulates glucose uptake in skeletal muscles and adipocytes. We found that serum exosome concentrations were increased significantly in the INS1-KDM6A-KO group. Skeletal muscles were isolated from WT and INS1-KDM6A-K mice. GLUT4 protein expression was upregulated in skeletal muscles in INS1-KDM6A-KO mice. Moreover, pancreatic islets isolated from the INS1-KDM6A-KO mice exhibited a notable increase in exosome release. Interestingly, exosomes from beta islets largely enhanced glucose uptake in cultured skeletal muscle cells and 3T3-L1 adipocytes. Meanwhile, beta cell-derived exosomes from KDM6A-KO mice upregulated GLUT4 in NOR-10 cells, especially in the presence of insulin. The findings suggest that beta cell-derived exosomes may play an important role in KDM6A deficiency-induced enhancement in insulin sensitivity likely via upregulation of GLUT4 in skeletal muscle cells and adipocytes. This work was supported by NIH R01 Grants - HL154147 and AG062375. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

An 8-Week study on the effects of high and Moderate-Intensity interval exercises on mitochondrial MOTS-C changes and their relation to metabolic markers in male diabetic sand rats

Mitochondrial dysfunction is a significant feature of type 2 diabetes. MOTS-C, a peptide derived from mitochondria, has positive effects on metabolism and exercise capacity. This study explored the impact of high and moderate-intensity interval exercises on mitochondrial MOTS-C alterations and their correlation with metabolic markers in male diabetic sand rats. Thirty male sand rats were divided into six groups: control, MIIT, DM + HIIT, DM + MIIT, DM, and HIIT (5 rats each). Diabetes was induced using a high-fat diet (HFD) combined with streptozotocin (STZ). The Wistar sand rats in exercise groups underwent 8 weeks of interval training of varying intensities. Post sample collection, protein expressions of PCG-1a, AMPK, and GLUT4 were assessed through Western blot analysis, while MOTS-C protein expression was determined using ELISA. Both exercise intensity and diabetes significantly affected the levels of PCG-1a, MOTS-C, GLUT4 proteins, and insulin resistance (p < 0.001). The combined effect of diabetes status and exercise intensity on these levels was also significant (p < 0.001). However, the diabetes effect varied when comparing high-intensity to moderate-intensity exercise. The moderate-intensity exercise group with diabetes showed higher levels of PCG-1a, MOTS-C, and GLUT4 proteins and reduced insulin resistance levels (p < 0.001). Exercise intensity (p = 0.022) and diabetes (p = 0.008) significantly influenced AMPK protein levels. The interplay between diabetes status and exercise intensity on AMPK protein levels was noteworthy, with the moderate-intensity diabetes group exhibiting higher AMPK levels than the high-intensity diabetes group (p < 0.001). In conclusion, exercise elevates the levels of PCG-1a, MOTS-C, GLUT4, and AMPK proteins, regulating insulin resistance in diabetic sand rats. Given the AMPK-MOTS-C mitochondrial pathway's mechanisms, interval exercises might enhance the metabolic rates and general health of diabetic rodents.

Unraveling the significance of PPP1R1A gene in pancreatic β-cell function: A study in INS-1 cells and human pancreatic islets

Background and aimsThe protein phosphatase 1 regulatory inhibitor subunit 1A (PPP1R1A) has been linked with insulin secretion and diabetes mellitus. Yet, its full significance in pancreatic β-cell function remains unclear. This study aims to elucidate the role of the PPP1R1A gene in β-cell biology using human pancreatic islets and rat INS-1 (832/13) cells. ResultsDisruption of Ppp1r1a in INS-1 cells was associated with reduced insulin secretion and impaired glucose uptake; however, cell viability, ROS, apoptosis or proliferation were intact. A significant downregulation of crucial β-cell function genes such as Ins1, Ins2, Pcsk1, Cpe, Pdx1, Mafa, Isl1, Glut2, Snap25, Vamp2, Syt5, Cacna1a, Cacna1d and Cacnb3, was observed upon Ppp1r1a disruption. Furthermore, silencing Pdx1 in INS-1 cells altered PPP1R1A expression, indicating that PPP1R1A is a target gene for PDX1. Treatment with rosiglitazone increased Ppp1r1a expression, while metformin and insulin showed no effect. RNA-seq analysis of human islets revealed high PPP1R1A expression, with α-cells showing the highest levels compared to other endocrine cells. Muscle tissues exhibited greater PPP1R1A expression than pancreatic islets, liver, or adipose tissues. Co-expression analysis revealed significant correlations between PPP1R1A and genes associated with insulin biosynthesis, exocytosis machinery, and intracellular calcium transport. Overexpression of PPP1R1A in human islets augmented insulin secretion and upregulated protein expression of Insulin, MAFA, PDX1, and GLUT1, while silencing of PPP1R1A reduced Insulin, MAFA, and GLUT1 protein levels. ConclusionThis study provides valuable insights into the role of PPP1R1A in regulating β-cell function and glucose homeostasis. PPP1R1A presents a promising opportunity for future therapeutic interventions.

A Metabolomics Study of the Effects of Eleutheroside B on Glucose and Lipid Metabolism in a Zebrafish Diabetes Model.

(1) Background: Diabetes is a common metabolic disease that seriously endangers human health. In the present study, we investigated the therapeutic effects of the active ingredient Eleutheroside B (EB) from the traditional Chinese medicine Eleutheroside on diabetes mellitus in a zebrafish model. Concomitant hepatic injury was also analysed, along with the study of possible molecular mechanisms using metabolomics technology. This work should provide some theoretical references for future experimental studies. (2) Methods: A zebrafish diabetes model was constructed by soaking in a 1.75% glucose solution and feeding a high-fat diet. The intervention drug groups were metformin (100 μg∙mL-1) and EB (50, 100, and 150 μg∙mL-1) via water-soluble exposure for 30 days. Glucose, TG, TC, LDL-C, and HDL-C were evaluated in different treatment groups. GLUT4 protein expression was also evaluated in each group, and liver injury was observed by HE staining. Metabolomics techniques were used to investigate the mechanism by which EB regulates endogenous markers and metabolic pathways during the development of diabetes. (3) Results: All EB treatment groups in diabetic zebrafish showed significantly reduced body mass index (BMI) and improved blood glucose and lipid profiles. EB was found to upregulate GLUT4 protein expression and ameliorate the liver injury caused by diabetes. Metabolomics studies showed that EB causes changes in the metabolic profile of diabetic zebrafish. These were related to the regulation of purine metabolism, cytochrome P450, caffeine metabolism, arginine and proline metabolism, the mTOR signalling pathway, insulin resistance, and glycerophospholipid metabolism. (4) Conclusions: EB has a hypoglycaemic effect in diabetic zebrafish as well as significantly improving disorders of glycolipid metabolism. The mechanism of action of EB may involve regulation of the mTOR signalling pathway, purine metabolism, caffeine metabolism, and glycerophospholipid metabolism.

Correlation of Differentially Expressed lncRNAs with Intestinal Flora Imbalance, Small Intestinal Permeability, and Glucose Uptake in T2DM Mice.

Diabetes is a major global health concern. This study aimed to investigate the correlation between differentially expressed lncRNAs in mice with type 2 diabetes mellitus (T2DM) and alterations in the intestinal flora and intestinal pathology. A T2DM mouse model was constructed by feeding mice a high-fat diet. Serum fat metabolism-related indices and insulin levels were biochemically detected. Serum inflammatory factors (IL-1β, IL-6, TNF-α, IL-10) and endotoxin (LPS) were measured by ELISA. Histopathological changes in the small intestines of mice were observed by HE. The short-chain fatty acid (SCFA) content was analyzed using GC-MS. Analysis of altered intestinal flora in T2DM mice was performed using a 16sRNA sequencing assay. Differences in lncRNA expression profiles in small intestinal tissues were analyzed using RNA-seq assays. Spearman's correlation analysis was used to correlate the expression of candidate lncRNAs with changes in differential gut flora. Spearman's correlation analysis was used to analyze the correlation between the expression of candidate differentially expressed lncRNAs, small intestinal permeability, and glucose absorption. We found that serum levels of LPS, BUN, Scr, TC, TG, LDL-C, IL-1β, IL-6, and TNF-α were elevated and levels of HDL-C, insulin, and IL-10 were decreased in T2DM mice. The ileal enterochromes of T2DM mice were disorganized and broken, the number of enterochromes was reduced, the local epithelial cells were necrotic, and the plasma membrane layer was locally absent. In addition, the protein expression of ZO-1 and occludin was decreased, and the protein expression of SGLT-1 and GLUT-2 was elevated in the model group compared to the control group.The levels of Acetic acid, Propionic acid and Butyric acid were decreased and the levels of Isobutyric acid andIsovaleric acid were increased, the abundance of beneficial bacteria was decreased and the abundance of harmfulbacteria was increased in the feces of T2DM mice. RNA-seq identified nine differentially expressed lncRNAs (LINC00675, Gm33838, Gm11655, LOC6613926, LOC6613788, LOC6613791, LOC6613795, Arhgap27os3, and A330023F24Rik). In addition, we found significant correlations between differentially expressed lncRNAs and a variety of intestinal flora, as well as between small intestinal permeability and glucose absorption. A significant correlation was observed between differentially expressed lncRNAs in the intestinal tissues of T2DM mice and intestinal flora imbalance, small intestinal permeability, and glucose absorption.

Sex-Specific Effects of Long-Term Antipsychotic Drug Treatment on Adipocyte Tissue and the Crosstalk to Liver and Brain in Rats.

Antipsychotic drug (APD) medication can lead to metabolic dysfunctions and weight gain, which together increase morbidity and mortality. Metabolically active visceral adipose tissue (VAT) in particular plays a crucial role in the etiopathology of these metabolic dysregulations. Here, we studied the effect of 12 weeks of drug medication by daily oral feeding of clozapine and haloperidol on the perirenal fat tissue as part of VAT of male and female Sprague Dawley rats in the context of complex former investigations on brain, liver, and blood. Adipocyte area values were determined, as well as triglycerides, non-esterified fatty acids (NEFAs), glucose, glycogen, lactate, malondialdehyde equivalents, ferric iron and protein levels of Perilipin-A, hormone-sensitive-lipase (HSL), hepcidin, glucose transporter-4 (Glut-4) and insulin receptor-ß (IR-ß). We found increased adipocyte mass in males, with slightly higher adipocyte area values in both males and females under clozapine treatment. Triglycerides, NEFAs, glucose and oxidative stress in the medicated groups were unchanged or slightly decreased. In contrast to controls and haloperidol-medicated rats, perirenal adipocyte mass and serum leptin levels were not correlated under clozapine. Protein expressions of perilipin-A, Glut-4 and HSL were decreased under clozapine treatment. IR-ß expression changed sex-specifically in the clozapine-medicated groups associated with higher hepcidin levels in the perirenal adipose tissue of clozapine-treated females. Taken together, clozapine and haloperidol had a smaller effect than expected on perirenal adipose tissue. The perirenal adipose tissue shows only weak changes in lipid and glucose metabolism. The main changes can be seen in the proteins examined, and probably in their effect on liver metabolism.

Artesunate improves glucose and lipid metabolism in db/db mice by regulating the metabolic profile and the MAPK/PI3K/Akt signalling pathway

BackgroundDiabetes is a metabolic disorder characterized by chronic hyperglycaemia. Chronic metabolic abnormalities and long-term hyperglycaemia may result in a wide range of acute and chronic consequences. Previous studies have demonstrated that artesunate(ART) has antidiabetic, anti-inflammatory, antiatherosclerotic, and other beneficial effects, but the specific regulatory mechanism is not completely clear. AimThis study investigated the effects of ART on metabolic disorders in type 2 diabetes mellitus (T2DM) model db/db mice and explored the underlying mechanisms involved. MethodsC57BL/KsJ-db/db mice were used to identify the targets and molecular mechanism of ART. Metabolomic methods were used to evaluate the efficacy of ART in improving T2DM-related metabolic disorders. Network pharmacology and transcriptomic sequencing were used to analyse the targets and pathways of ART in T2DM. Finally, molecular biology experiments were performed to verify the key targets and pathways selected by network pharmacology and transcriptomic analyses. ResultsAfter a 7-week ART intervention (160 mg/kg), the glucose and lipid metabolism levels of the db/db mice improved. Additionally, the oxidative stress indices, namely, the MDA and SOD levels, significantly improved (p<0.01). Linoleic acid and glycerophospholipid metabolism, amino acid metabolism, bile acid synthesis, and purine metabolism disorders in db/db mice were partially corrected after ART treatment. Network pharmacology analysis identified important targets of ART for the treatment of metabolic disorders in T2DM . These targets are involved in key signalling pathways, including the highest scores observed for the PI3K/Akt signalling pathway. Transcriptomic analysis revealed that ART could activate the MAPK signalling pathway and two key gene targets, HGK and GADD45. Immunoblotting revealed that ART increases p-PI3K, p-AKT, Glut2, and IRS1 protein expression and suppresses the phosphorylation of p38, ERK1/2, and JNK, returning HGK and GADD45 to their preartesunate levels. ConclusionTreatment of db/db mice with 160 mg/kg ART for 7 weeks significantly reduced fasting blood glucose and lipid levels. It also improved metabolic imbalances in amino acids, lipids, purines, and bile acids, thereby improving metabolic disorders. These effects are achieved by activating the PI3K/AKT pathway and inhibiting the MAPK pathway, thus demonstrating the efficacy of the drug.