Enzymes Of Glucose Metabolism Research Articles

Multi Targeted Activity of Cocculus hirsutus through Modulation of DPP-IV and PTP-1B Leading to Enhancement of Glucose Uptake and Attenuation of Lipid Accumulation.

Multi-targeted therapies are gaining attention in the management of multifactorial diseases due to their poly pharmacology, enhanced potency and reduced toxicity. Metabolic disorders like Type 2 diabetes mellitus (T2DM) and obesity necessitate multi-targeted therapy to improve insulin sensitivity, regulate glucose homeostasis and support weight loss. Medicinal plants rich in bioactive compounds exhibit multi-targetted action with minimal side effects. In the current study, Cocculus hirsutus methanol extract (CME) and its hydromethanolic fraction (HMF) were investigated for their multi-target potential. Significant inhibition of Dipeptidyl peptidase IV (DPP-IV), a key enzyme in glucose metabolism was observed due to CME (54%) and HMF (70%) at 10µg/ml and 1µg/ml respectively. Protein Tyrosine Phosphatase 1B (PTP-1B), involved in the regulation of insulin signalling, was also inhibited by CME (67%) and HMF (73%) at 10µg/ml concentration. An increase in glucose uptake was observed due to CME (62% and 65%) and HMF (63% and 68%) in 3T3-L1 adipocytes and L6 myotubes at 100ng/ml. Further, investigation of HMF showed a decrease in lipid accumulation by 63% at 1µg/ml in 3T3-L1 cells. Interestingly, HMF improved insulin sensitivity by upregulating GLUT4 expression (p < 0.05) via the PI3K/AKT pathway in both 3T3-L1 adipocytes and L6 myotubes. An inhibition in lipid accumulation was also observed by suppression of Peroxisome proliferator-activated receptor γ (PPARγ) (p < 0.05), a key regulator of adipogenesis in 3T3-L1 adipocytes. Gas chromatography-mass spectrometry analysis of the HMF showed the major component to be 3-methylmannoside (26.52%).

DPP-IV Inhibition by Solubilized Elastin Peptides from Yellowtail Bulbus Arteriosus Suppresses Ultraviolet-B-Induced Photoaging in Hairless Mice

Skin aging is intrinsic and extrinsic. Intrinsic, or chronological, skin aging is an inevitable process of chronological and physiological alterations. The factors contributing to extrinsic skin aging involve sunlight, nutrients, and stress. Thus, extrinsic aging is thought to be superimposed over intrinsic aging and depends on the intensity and duration of environmental exposure and skin type (e.g., dry skin, oily skin, or eczema). The most significant extrinsic aging factor is UV radiation, which causes cellular senescence in a process known as photoaging. This study aimed to illuminate the mechanism whereby solubilized elastin peptide lotion (EL) from the bulbus arteriosus of yellowtail (Seriola quinqueradiata) prevents skin photoaging in hairless mice. EL reduced wrinkle formation, epidermal skin thickness, and Ki67 (cell growth marker) mRNA expression in skin tissues from ultraviolet B (UVB)-irradiated mice. EL treatment also reduced glyoxalase-1 (key enzyme of glucose metabolism) levels in skin tissue. Although no significant differences in collagen and elastin contents were found in dermal areas, matrix metalloproteinase-12 (wrinkle-related marker) expression was reduced following EL application. Furthermore, skin DPP-IV/CD26 (new senescence marker) levels decreased following EL treatment in photoaging model mice. These results suggest that EL moderates skin damage caused by UVB irradiation by regulating senescence-related molecule expression.

Salutary effect of &lt;i&gt;Commelina benghalensis&lt;/i&gt; (Linn.) aerial parts on streptozotocin induced diabetes linked complications in rat: Effective extract selection study

The experiment was designed to identify the most effective extract of Commelina benghalensis aerial parts for the rectification of carbohydrate metabolic disorder, oxidative stress and hyperlipidemia in streptozotocin-induced diabetic rats, developed with a single intramuscular injection of streptozotocin (4 mg/0.1 M citrate buffer/0.1 kg body weight). Diabetic rats were treated with 0.02 g of hydro-methanol (60:40) or hydro-ethanol (60:40) or aqueous extract orally per 0.1 kg body weight in 0.5 ml distilled water for 28 days and sacrificed on 29th day. Glycemic sensors levels, carbohydrate metabolizing enzyme activities, lipid profile, oxidative stress, toxicity markers, and pancreatic histological changes were assessed using standard protocols. Treatment with mentioned extracts of Commelina benghalensis significantly (p&lt;0.05) improved body weight, fasting blood glucose, serum insulin, lipid profile, and carbohydrate metabolic enzyme kinetics in the liver, kidney and skeletal muscle in treated groups compared to untreated diabetic control group. Additionally, treatment of said extracts of Commelina benghalensis significantly restored (p&lt;0.05) the levels of oxidative stress sensors and pancreatic histology towards untreated control group. Among the extracts, hydro-ethanolic extract showed highest efficacy for rectifying glycemic status, lipid profile, and oxidative stress condition for developing a safe, affordable and multi-targeted anti-diabetic herbal drug.

PYGB targeted by androgen receptor contributes to tumor progression and metabolic reprogramming in esophageal squamous carcinoma

The incidence and mortality rates of esophageal squamous cell carcinoma (ESCC) are conspicuously augmented in men in contrast to women. The androgen receptor (AR), prevalently associated with the manifestation of male characteristics, is regarded as a pivotal determinant in tumor progression. Nevertheless, its exact role in ESCC remains insufficiently delineated. In this study, we probed the expression levels of AR and glucose metabolism enzymes in ESCC tissues by means of immunohistochemistry. We exploited chromatin immunoprecipitation and dual luciferase reporter assays to delve into the transcriptional regulatory interrelationships between AR and these enzymes. A gamut of molecular techniques-including multi-omics sequencing, colony formation assays, cell counting kit 8 (CCK8), 5-Ethynyl-2'-deoxyuridine (EdU) incorporation assays, wound-healing assays, transwell migration assays, extracellular acidification rate (ECAR) measurements, lipid droplet fluorescence imaging, and xenograft models-were enlisted to illuminate the functions of these enzymes within ESCC cells. Our discoveries manifested that AR expression was strikingly higher in male ESCC tissues than in their female counterparts. Significantly, we discerned that glycogen phosphorylase B (PYGB), a cardinal enzyme implicated in glucose metabolism, demonstrated not only a positive correlation with AR expression but also an association with adverse prognostic outcomes for ESCC patients. Moreover, AR directly binds to the promoter region of the PYGB gene, thereby potentiating its transcriptional activity. This upregulation of PYGB was ascertained to facilitate proliferation, invasion, and metastasis among ESCC cells while intensifying glycolysis and modifying lipid metabolism pathways within these cells. In animal models employing nude mice, elevated PYGB levels were witnessed to expedite subcutaneous tumor growth as well as lung metastasis. Collectively, our study establishes PYGB as a direct target of AR that assumes an indispensable role in both tumor progression and metabolic reprogramming affiliated with ESCC, thus paving novel avenues for therapeutic strategies centered on metabolic intercessions.

Knockout of &lt;i&gt;Hsp70&lt;/i&gt; genes modulates age-related transcriptomic changes in leg muscles, reduces locomotion speed and lifespan of &lt;i&gt;Drosophila melanogaster&lt;/i&gt;

The study investigated the effect of knockout of six Hsp70 genes (orthologues of the mammalian genes Hspa1a, Hspa1b, Hspa2 and Hspa8) on age-related changes in gene expression in the legs of Drosophila melanogaster, which contain predominantly skeletal muscle bundles. For this, the leg transcriptomic profile was examined in males of the w1118 control line and the Hsp70– line on the 7th, 23rd and 47th days of life. In w1118 flies, an age-related decrease in the locomotion (climbing) speed (a marker of functional state and endurance) was accompanied by a pronounced change in the transcriptomic profile of the leg skeletal muscles, which is conservative in nature. In Hsp70– flies, the median lifespan was shorter and the locomotion speed was significantly lower compare to the control; at the same time, complex changes in the age-related dynamics of the skeletal muscle transcriptome were observed. Mass spectrometry-based quantitative proteomic showed that 47-day-old Hsp70– flies, compared with w1118, demonstrated multidirectional changes in the content of key enzymes of glucose metabolism and fat oxidation (glycolysis, pentose phosphate pathway, Krebs cycle, beta-oxidation and oxidative phosphorylation). Such dysregulation may be associated with a compensatory increase in the expression of other genes encoding chaperones (small Hsp, Hsp40, 60, and 70), which regulate specific sets of target proteins. Taken together, our data show that knockout of six Hsp70 genes slightly reduces the median lifespan of flies, but significantly reduces the locomotion speed, which may be associated with complex changes in the transcriptome of the leg skeletal muscles and with multidirectional changes in the content of key enzymes of energy metabolism.

Identification and characterisation of 'No apical meristem; Arabidopsis transcription activation factor; Cup-shape cotyledon' (NAC) family transcription factors involved in sugar accumulation and abscisic acid signalling in grape (Vitis vinifera).

The 'No apical meristem; Arabidopsis transcription activation factor; Cup-shape cotyledon' (NAC) transcription factors are pivotal in plant development and stress response. Sucrose-non-fermenting-related protein kinase 1.2 (SnRK1) is a key enzyme in glucose metabolism and ABA signalling. In this study, we used grape (Vitis vinifera ) calli to explore NAC's roles in sugar and ABA pathways and its relationship with VvSnRK1.2 . We identified 19 VvNACs highly expressed at 90days after blooming, coinciding with grape maturity and high sugar accumulation, and 11 VvNACs randomly selected from 19 were demonstrated in response to sugar and ABA treatments. VvNAC26 showed significant response to sugar and ABA treatments, and its protein, as a nucleus protein, had transcriptional activation in yeast. We obtained the overexpression (OE-VvNAC26 ) and RNA-inhibition (RNAi-VvNAC26 ) of VvNAC26 in transgenic calli by Agrobacterium tumefaciens -mediated transformation. We found that VvNAC26 negatively influenced fructose content. Under sugar and ABA treatments, VvNAC26 negatively influenced the expression of most sugar-related genes, while positively influencing the expression of most ABA pathway-related genes. Dual-luciferase reporter experiments demonstrated that VvNAC26 significantly upregulates VvSnRK1.2 promoter expression in tobacco (Nicotiana benthamiana ) leaves, although this process in grape calli requires ABA. The levels of sugar content, sugar-related genes, and ABA-related genes fluctuated significantly in OE-VvNAC26 +RNAi-VvSnRK1.2 and OE-VvSnRK1.2 +RNAi-VvNAC26 transgenic calli. These findings indicated that VvNAC26 regulates sugar metabolism and ABA pathway, displaying synergistic interactions with VvSnRK1.2 .

In Vitro Treatment with Metformin Significantly Reduces Senescent B Cells Present in the Adipose Tissue of People with Obesity

Our previous work has shown that senescent B cells accumulate in the human adipose tissue (AT) from people with obesity, where they express transcripts for markers associated with the senescence-associated secretory phenotype (SASP) and secrete multiple inflammatory mediators. These functions of AT-derived B cells are metabolically supported. To show that Metformin (MET), a widely used hypoglycemic and antidiabetic drug, is able at least in vitro to decrease frequencies, secretory profile, and metabolic requirements of senescent B cells isolated from the AT from people with obesity. We recruited adult females with obesity (n = 8, age 40 ± 2 y, BMI range: 33-42) undergoing breast reduction surgery, who donated their discarded subcutaneous AT. B cells from stromal vascular fractions isolated after collagenase digestion of the AT were evaluated after in vitro incubation with MET (1 mM × 106 B cells) or with a medium for the following measures. The expression of transcripts for SASP-associated markers (p16INK4a and p21CIP1/WAF1) measured by quantitative polymerase chain reaction (qPCR); secretion of inflammatory cytokines (TNF-α, IL-6, IFN-γ and IL-17A) measured by a Cytometric Bead Array); metabolic characteristics as identified by a glycolytic test and Seahorse technology, and by the expression of transcripts for glucose transporters and metabolic enzymes involved in glucose metabolic pathways, measured by qPCR. To examine differences between MET-treated compared with untreated groups, paired Student's t tests (two-tailed) were employed. MET in vitro was able to reduce frequencies and numbers of senescent B cells, as identified by staining with β-galactosidase, as well as the secretion of inflammatory cytokines, the expression of transcripts for SASP, and metabolic markers that support intrinsic B cell inflammation. Our results provide evidence to support the beneficial effects of MET in reducing AT-related inflammation through its effects on senescent B cells.

Nutritional Composition and Effect of Loquat Fruit (Eriobotrya japonica L. var. Navela) on Lipid Metabolism and Liver Steatosis in High-Fat High-Sucrose Diet-Fed Mice.

Loquat (Eriobotrya japonica L.) is a popular fruit known for its sweet and slightly tangy flavor, which is widely consumed both fresh and in various processed forms. This study aimed to analyze the biochemical composition of loquat juice and investigate its metabolic benefits in mice fed a high-fat/high-sucrose diet (HFSD). Mice were fed either a standard diet or an HFSD and received or not the loquat juice at 4 or 8 mL/kg body weight for 8 weeks. Body weight, food efficiency ratio, plasma lipoprotein profile, plasma glucose, and lipid indices were monitored throughout the experiment. At the end of the experiment, additional assessments were performed, including lipid content measurements in liver, adipose tissue, bile, and feces; hepatic antioxidant enzyme activities (superoxide dismutase and catalase); hepatic malondialdehyde content; plasma biomarkers of liver injury; liver histology; and organ relative weight. Feeding mice with the HFSD resulted in a significant perturbation in lipid and glucose metabolism, obesity, liver steatosis, and oxidative stress-related enzymes. However, the concomitant administration of loquat juice significantly corrected this imbalance. Fresh loquat juice is low in fat and protein, moderately sugary, and energetically light; however, it is rich in minerals, vitamin C, and various phytochemicals compounds, such as phenolic acids, flavonoids, and carotenoids. The loquat juice could be considered a functional food and could be valorized through the extraction of active substances and their use as food supplements to prevent lipid metabolism disorders and the resulting health complications.

Targeting PDHK1 by DCA to Restore NK Cell Function in Hepatocellular Carcinoma.

Pyruvate dehydrogenase complex is a crucial enzyme involved in the oxidation of glucose. It is regulated by pyruvate dehydrogenase kinase (PDHK) and pyruvate dehydrogenase phosphatase. Studies have demonstrated that PDHK1, a key enzyme in glucose metabolism, behaves like oncogenes. It is highly expressed in tumors and is associated with poor patient prognosis. However, there is limited research on how PDHK1 affects immune cell function. We have established a model of NK cell exhaustion to investigate the impact of dichloroacetate (DCA) on NK cell function. The production of granzyme B, IFNγ, TNFα, and CD107a by NK cells was explored by flow cytometry. The real-time live-cell imaging system was used to monitor the ability of NK cells against tumor cells. The Seahorse analyzer was utilized to measure the oxygen consumption rate and extracellular acidification rate of NK cells. A mouse model was used to investigate the potential of combining DCA with adjuvant NK cell infusion. Our study demonstrated that the hepatocellular carcinoma microenvironment mediated NK cellular exhaustion and high expression of PDHK1 and reduced cytokine secretion. We discovered that the PDHK1 inhibitor DCA enhances the activity and function of exhausted NK cells infiltrating the tumor microenvironment. Furthermore, in a s.c. hepatocellular carcinoma mouse model, DCA combined with NK cell treatment resulted in retarding cancer progression. This study indicates the potential of DCA in rescuing NK cell exhaustion and eliciting antitumor immunity.

Fenitrothion induces glucose metabolism disorders in rat liver BRL cells by inhibiting AMPKα and IRS1/PI3K/AKT signaling pathway

Fenitrothion (FNT) is a common organophosphorus pesticide that is widely used in both agricultural and domestic pest control. FNT has been frequently detected in various environmental media, including the human body, and is a notable contaminant. Epidemiological investigations have recently shown the implications of exposure to FNT in the incidence of various metabolic diseases, such as diabetes mellitus in humans, indicating that FNT may be a potential endocrine disruptor. However, the effects of FNT exposure on glucose homeostasis and their underlying mechanisms in model organisms remain largely unknown, which may limit our understanding of the health risks of FNT. In this study, FNT (45, 90, 180, and 450μM) exposure model of rat hepatocytes (Buffalo Rat Liver, BRL cells) was established to investigate the effects and potential mechanisms of its toxicity on glucose metabolism. Several key processes of glucose metabolism were detected in this study. The results showed significantly increased glucose levels in the culture medium and decreased glycogen content in the FNT-exposed BRL cells. The results of quantitative real-time PCR and enzymology showed the abnormal expression of genes and activity/content of glucose metabolic enzymes involved in glucose metabolism, which might promote gluconeogenesis and inhibit glucose uptake, glycolysis, and glycogenesis. Furthermore, gluconeogenesis and glycolytic were carried out in the mitochondrial membrane. The abnormal of mitochondrial membrane potential may be a potential mechanism underlying FNT-induced glucose metabolism disorder. In addition, the mRNA and protein expression implicated that FNT may disrupt glucose metabolism by inhibiting the AMPKα and IRS1/PI3K/AKT signaling pathways. In conclusion, results provide in vitro evidence that FNT can cause glucose metabolism disorder, which emphasizes the potential health risks of exposure to FNT in inducing diabetes mellitus.

Methanolic extracts of litchi (Litchi chinensis Sonn.): A novel approach of targeting glucose-6-phosphate dehydrogenase for liver cancer therapy

Cancer metabolism has emerged as a potential target for innovative therapeutic approaches in the treatment of cancer. Cancer metabolism has received much attention, particularly in relation to glucose metabolism. It has been observed that human malignancies have high levels of glucose-6-phosphate dehydrogenase (G6PD) activity which is an important enzyme of glucose metabolism. This overactivity is associated with the cell death and angiogenesis, highlighting its potential as a viable target for cancer treatment. This study was conducted to examine the methanolic extracts from the seeds, bark and leaves of litchi (Litchi chinensis Sonn.) in order to discover effective compounds targeting G6PD and potentially active entities against liver cancer. Plant extract screening for the target protein was carried out through enzymatic activity assay. The recombinant plasmid pET-24a-HmG6PD was expressed in E. coli (BL21-DE3) strain, then purified and assessed using metal affinity chromatography with Ni-NTA columns and SDS-PAGE. The cytotoxicity of plant extracts against liver cancer HepG2 cells was assessed using the MTT assay. All three extracts demonstrated significant inhibitory effects (>80% inhibition) against G6PD. They were then subjected to testing at various concentrations, and their IC50 values were subsequently determined. The extracts of litchi (leaf, IC50: 1.199μg/mL; bark, IC50: 2.350μg/mL; seeds, IC50: 1.238μg/mL) displayed significant inhibition of G6PD activity at lower concentrations. Subsequently, the leaf extract of litchi was further assessed for its impact on HepG2 cell lines in a dose-dependent manner and exhibited strong potential as an inhibitor of cancer cell progression. Moreover, the results of acute toxicity study in mice revealed nontoxic effects of litchi leaf extract on hepatocytes. The results imply that Litchi chinensis leaf extract could be considered as a promising candidate for safer drug development in the treatment of liver cancer.

Changes in glucose metabolism, C-reactive protein, and liver enzymes following intake of NAD + precursor supplementation: a systematic review and meta‐regression analysis

BackgroundThere are contradictory effects regarding the effect of NAD + precursor on glucose metabolism and liver enzymes. In order to obtain a better viewpoint from them, this study aimed to comprehensively investigate the effects of NAD + precursor supplementation on glucose metabolism, C-reactive protein (CRP), and liver enzymes.MethodsPubMed/MEDLINE, Web of Science, SCOPUS, and Embase databases were searched using standard keywords to identify all controlled trials investigating the glucose metabolism, CRP, and liver enzymes effects of NAD + precursor. Pooled weighted mean difference (WMD) and 95% confidence intervals (95% CI) were achieved by random-effects model analysis for the best estimation of outcomes.ResultsForty-five articles with 9256 participants’ were included in this article. The pooled findings showed that NAD + precursor supplementation had a significant increase in glucose (WMD: 2.17 mg/dL, 95% CI: 0.68, 3.66, P = 0.004) and HbA1c (WMD: 0.11, 95% CI: 0.06, 0.16, P < 0.001) as well as a significant decrease in CRP (WMD: -0.93 mg/l, 95% CI -1.47 to -0.40, P < 0.001) compared with control group, and was not statistically significant with respect to insulin and homeostasis model assessment of insulin resistance (HOMA-IR). However, we found no systemic changes in aspartate transaminase (AST), alanine transaminase (ALT), or alkaline phosphatase (ALP) levels after NAD + precursor supplementation. The results of the subgroup analysis showed that the intake of NAD + precursor during the intervention of more than 12 weeks caused a greater increase in the glucose level. Furthermore, Nicotinic acid supplementation (NA) causes a greater increase in glucose and HbA1c levels than nicotinamide (NE) supplementation.ConclusionsOverall, these findings suggest that NAD + precursor supplementation might have an increase effect on glucose metabolism as well as a decrease in CRP.

Glucose 6 phosphate dehydrogenase overexpression rescues the loss of cognition in the double transgenic APP/PS1 mouse model of Alzheimer’s disease

Mice models of Alzheimer's disease (APP/PS1) typically experience cognitive decline with age. G6PD overexpressing mice (G6PD-Tg) exhibit better protection from age-associated functional decline including improvements in metabolic and muscle functions as well as reduced frailty compared to their wild-type counterparts. Importantly G6PD-Tg mice show diminished accumulation of DNA oxidation in the brain at different ages in both males and females. To further explore the potential benefits of modulating the G6PD activity in neurodegenerative diseases, triple transgenic mice (3xTg G6PD) were generated, overexpressing APP, PSEN1, and G6PD genes. The cognitive decline characteristic of APP/PS1 mice was prevented in 3xTg G6PD mice, despite similar amyloid-β (Aβ) levels in the hippocampus. This challenges the dominant hypothesis in Alzheimer's disease (AD) etiology and the majority of therapeutic efforts in the field, based on the notion that Aβ is pivotal in cognitive preservation. Notably, the antioxidant properties of G6PD led to a decrease in oxidative stress parameters, such as improved GSH/GSSG and GSH/CysSSG ratios, without major changes in oxidative damage markers. Additionally, metabolic changes in 3xTg G6PD mice increased brain energy status, countering the hypometabolism observed in Alzheimer's models. Remarkably, a higher respiratory exchange ratio suggested increased carbohydrate utilization. The relative failures of Aβ-targeted clinical trials have raised significant skepticism on the amyloid cascade hypothesis and whether the development of Alzheimer's drugs has followed the correct path. Our findings highlight the significance of targeting glucose-metabolizing enzymes rather than solely focusing on Aβ in Alzheimer's research, advocating for a deeper exploration of glucose metabolism's role in cognitive preservation.

Fomentariol, a Fomes fomentarius Compound, Exhibits Anti-Diabetic Effects in Fungal Material: An In Vitro Analysis

The present study screened various fungal species for inhibitors of alpha-glucosidase, alpha-amylase, and DPP-4, enzymes that are crucial in carbohydrate metabolism. Ethanolic extracts exhibited superior inhibitory activity compared to water extracts, suggesting their potential as sources of anti-diabetic agents. Further fractionation revealed fomentariol from Fomes fomentarius as a potent inhibitor of alpha-glucosidase and DPP-4, with higher activity against alpha-glucosidase than acarbose. Fomentariol presents a novel avenue for diabetes management, demonstrating the simultaneous inhibition of key enzymes in glucose metabolism. However, comprehensive clinical studies are needed to evaluate its safety and efficacy in humans.

Regulation of macrophage polarization and glucose metabolism by the ERK/MAPK-HK1 signaling pathway in paraquat-induced acute lung injury

Acute lung injury is the leading cause of paraquat (PQ) poisoning-related mortality. The mechanism by which macrophages are involved in PQ-induced acute lung injury remains unclear. In recent years, the role of metabolic reprogramming in macrophage functional transformation has received significant attention. The current study aimed to identify the role of altered macrophage glucose metabolism and molecular mechanisms in PQ poisoning-induced acute lung injury. We established a model of acute lung injury in PQ-intoxicated mice via the intraperitoneal injection of PQ. PQ exposure induces macrophage M1 polarization and promotes the release of inflammatory factors, which causes the development of acute lung injury in mice. In vitro analysis revealed that PQ altered glucose metabolism, which could be reversed by siRNA transfection to silence the expression of HK1, a key enzyme in glucose metabolism. RNA sequencing revealed that the ERK/MAPK pathway was the crucial molecular mechanism of PQ pathogenesis. Further, U0126, an ERK inhibitor, could inhibit PQ-induced HK1 activation and macrophage M1 polarization. These findings provide novel insights into the previously unrecognized mechanism of ERK/MAPK-HK1 activation in PQ poisoning.

Dual roles of HK3 in regulating the network between tumor cells and tumor-associated macrophages in neuroblastoma

Neuroblastoma (NB) is the most common and deadliest extracranial solid tumor in children. Targeting tumor-associated macrophages (TAMs) is a strategy for attenuating tumor-promoting states. The crosstalk between cancer cells and TAMs plays a pivotal role in mediating tumor progression in NB. The overexpression of Hexokinase-3 (HK3), a pivotal enzyme in glucose metabolism, has been associated with poor prognosis in NB patients. Furthermore, it correlates with the infiltration of M2-like macrophages within NB tumors, indicating its significant involvement in tumor progression. Therefore, HK3 not only directly regulates the malignant biological behaviors of tumor cells, such as proliferation, migration, and invasion, but also recruits and polarizes M2-like macrophages through the PI3K/AKT-CXCL14 axis in neuroblastoma. The secretion of lactate and histone lactylation alterations within tumor cells accompanies this interaction. Additionally, elevated expression of HK3 in M2-TAMs was found at the same time. Modulating HK3 within M2-TAMs alters the biological behavior of tumor cells, as demonstrated by our in vitro studies. This study highlights the pivotal role of HK3 in the progression of NB malignancy and its intricate regulatory network with M2-TAMs. It establishes HK3 as a promising dual-functional biomarker and therapeutic target in combating neuroblastoma.

Abstract 2055: Pyruvic Carboxylase In Macrophages Aggravates Atherosclerosis By Regulating Metabolism Reprogramming To Promote Inflammatory Responses Through Hif-1 Signal Pathway

Background: Atherosclerotic patients exhibit abnormal glucose metabolism. Pyruvic carboxylase (PC) is a key enzyme in glucose metabolism which converts pyruvate into oxaloacetate, an intermediate reactant in both gluconeogenesis and tricarboxylic acid cycle. However, the role of PC in atherosclerosis remains unclear. Aims: We aimed to explore a potential target in macrophage metabolism for atherosclerosis treatment. Methods: We generated macrophage-specific PC knockout mice ( PC M KO ) by crossbreeding the PC fl/fl mice with L yz 2 -cre mice expressing Cre-recombinase in macrophages. Bone marrow transplantation was conducted to generate PC fl/fl / Apoe -/- and PC M KO / Apoe -/- chimaera. Mice were administered with AAV- PCSK9 DY followed by a 12-week high-fat diet (HFD) to induce atherosclerosis. Results: PC was upregulated in macrophages of human and mice with atherosclerosis. Macrophage-specific PC deficiency mitigated HFD-induced atherosclerotic lesions in both Apoe -/- mice and mice injected with AAV- PCSK9 DY . PC deletion reduced reactive oxygen species overproduction and mitochondrial damage in macrophages. Transcriptomics revealed that PC activated the HIF-1 signal pathway by initiating metabolic reprogramming in macrophages. By preventing HIF-1α from proteasome degradation, PC induced nuclear translocation of HIF-1α in atherosclerotic aortic roots. HIF-1α stabilizer, dimethyloxalylglycine, reversed the anti-inflammatory effect of PC in macrophages exposed to hypoxia, whereas the inhibition of HIF-1α impeded the transformation of pro-inflammatory macrophages to anti-inflammatory macrophages induced by PC overexpression. Dimethyloxalylglycine reversed the beneficial effects of macrophage PC deficiency on atherosclerosis. Conclusion: Macrophage PC aggravates atherosclerosis by regulating metabolic reprogramming, thereby promoting inflammatory responses in macrophages through HIF-1 signal pathway.

Analysis of Lysine Metabolism in a Rat Model of Type 2 Diabetes Reveals Modulation of Endocytosis and Glucose Metabolism

Lysine is an essential amino acid that serves as a building block for proteins and plays a role in metabolic processes. While a recent study provided evidence that lysine is beneficial for hypertension-associated kidney disease, possibly through inhibiting renal tubular reabsorption and forming new lysine conjugates, knowledge about the role of lysine in diabetic nephropathy (DN) is rudimentary. Therefore, the aim of the study was to investigate the role of lysine in kidney function in the setting of DN and its underlying mechanisms. We hypothesized that lysine may impact the kidneys in the following ways: 1) by mediating protein endocytosis in proximal tubules; 2) by altering protein abundance in the kidneys and other organs; and 3) by disrupting metabolic pathways through the formation of conjugates or degradation products. We investigated the effects of lysine on proximal tubule endocytosis and other organs using proteomic approaches and studied changes in lysine conjugates and metabolic products using targeted metabolomics. The results of urinary proteomics suggested that lysine’s impact on endocytosis may be associated with the inhibition of megalin and cubilin. Furthermore, lysine affected proteins related to glucose metabolism. Subsequently, we proceeded to investigate the influence of lysine on various organs in Type 2 Diabetic Nephropathy (T2DN) rats. Gene Ontology (GO) enrichment revealed that lysine exerts tissue-specific effects on different organs, with pathways enriched in the kidney including phagocytosis and enzyme inhibitor activity. Additionally, within the kidney, the lysine-treated group showed downregulation of glycolysis-related enzymes. The metabolomics results showed that lysine leads to a decrease in glucose and an increase in fructose 1,6-bisphosphate, while also resulting in an upregulation of related metabolites in the tricarboxylic acid cycle (TCA cycle). Our findings showed changes in the protein composition involved in lysine-mediated endocytosis and the impact of lysine on glucose metabolism enzymes and metabolites. The specific molecular mechanisms are still under investigation. R01 DK135644 and I01 BX004024 (to AS). 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.

O-GlcNAc transferase plays dual antiviral roles by integrating innate immunity and lipid metabolism

Abstract Challenge of host cells with viral pathogens induces robust metabolic reprogramming; however, whether viral component(s) is detected by metabolic enzyme remains completely unknown. Our previous study identified the O-GlcNAc transferase (OGT), an important glucose metabolic enzyme, as a crucial mediator of MAVS-dependent antiviral response. Here, by studying a mouse model with enzyme-inactive OGT, we demonstrate an enzyme-independent function of OGT in limiting influenza A virus (IAV) infection, in addition to its enzyme-dependent effect on MAVS. Biochemical studies reveal a critical antiviral effect of OGT binding with IAV genomic RNA via its N-terminal tetratricopeptide repeats-4 domain. Binding with viral RNA causes a robust translocation of nuclear OGT to cytosolic lipid droplets (LDs) and subsequently antagonizes LD accumulation via destabilizing perilipin 2. This LD-targeting effect of OGT limits IAV replication without altering MAVS signaling. Our findings reveal OGT as a multifaceted metabolic sensor by integrating MAVS-dependent innate immune signaling and lipid metabolism.

Comprehensive analysis of histophysiology, transcriptome and metabolome tolerance mechanisms in black porgy (Acanthopagrus schlegelii) under low temperature stress

Low temperature stress has adverse effects on fish growth and reproduction, causing huge economic losses to the aquaculture industry. Especially, black porgy (Acanthopagrus schlegelii) farming industry in north of Yangtze River has been severely affected by low temperature for a long time. To explore the tolerance mechanism of black porgy to low temperature stress, the experiment was designed. The liver and gill tissues of black porgy were taken from the water temperature point of 15°C (control group named as CG), 3.8°C (cold sensitive group named as CS) and 2.8°C (cold tolerant group named as CT) with a cooling rate of 3°C/d from 15°C for histophysiology, transcriptomics and metabolomics analysis. After cold stress, the histological results showed that the nucleus of the black porgy liver tissue appeared swelling, the cell arrangement was disordered; meanwhile the gill lamellae were twisted and broken, the epidermis was detached and aneurysm appeared. In addition, the expression of antioxidant, glucose metabolism and immune-related enzymes in the liver and gill of black porgy also changed significantly after low temperature stress. By analyzing the transcriptome and metabolome dates of black porgy liver, 3474 differentially expressed genes (DEGs) and 689 differentially expressed metabolites (DEMs) involved in low temperature stress were identified, respectively. The results of the transcriptome and metabolome combined analysis showed that individuals in the CS group mainly supplied energy to the body through lipid metabolism and amino acid metabolism, and meanwhile the apoptosis pathway was activated. While, individuals in the CT group mainly through glucose metabolism and steroid hormone biosynthesis to supply energy for the body. The validation results of qPCR on eight functional genes further demonstrated the reliability of RNA-Seq data. In summary, the results provide molecular information about adaptation to climate change and genetic selection of black porgy.