Enzymes Of Gluconeogenesis Research Articles

Piperlongumine based nanomedicine impairs glycolytic metabolism in triple negative breast cancer stem cells through modulation of GAPDH & FBP1

BackgroundTriple negative breast cancer (TNBC) is the most aggressive subtype of breast cancer and exhibits high rate of chemoresistance, metastasis, and relapse. This can be attributed to the failure of conventional therapeutics to target a sub-population of slow cycling or quiescent cells called as cancer stem cells (CSCs). Therefore, elimination of CSCs is essential for effective TNBC treatment. PurposeResearch suggests that breast CSCs exhibit elevated glycolytic metabolism which directly contributes in maintenance of stemness, self-renewability and chemoresistance as well as in tumor progression. Therefore, this study aimed to target rewired metabolism which can serve as Achilles heel for CSCs population and have far reaching effect in TNBC treatment. MethodsWe used two preclinical models, zebrafish and nude mice to evaluate the fate of nanoparticles as well as the therapeutic efficacy of both piperlongumine (PL) and its nanomedicine (PL-NPs). ResultsIn this context, we explored a phytochemical piperlongumine (PL) which has potent anti-cancer properties but poor pharmacokinetics impedes its clinical translation. So, we developed PLGA based nanomedicine for PL (PL-NPs), and demonstrated that it overcomes the pharmacokinetic limitations of PL, along with imparting advantages of selective tumor targeting through Enhanced Permeability and Retention (EPR) effect in zebrafish xenograft model. Further, we demonstrated that PL-NPs efficiently inhibit glycolysis in CSCs through inhibition of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) by modulating glutathione S-transferase pi 1 (GSTP1) and upregulation of fructose-1,6-bisphosphatase 1 (FBP1), a rate-limiting enzyme in gluconeogenesis. We also illustrated that inhibition of glycolysis results in overall tumor regression in two preclinical models. ConclusionThis study discusses novel mechanism of action by which PL acts on CSCSs. Taken together our study provides insight into development of PL based nanomedicine which could be exploited in clinics to achieve complete eradication of TNBC by targeting CSCs.

Protein Lactylation Modification and Proteomics Features in Cirrhosis Patients after UC-MSC Treatment.

Umbilical cord mesenchymal stem cell (UC-MSC) therapy improves liver function in liver cirrhosis patients. This study aimed to elucidate the therapeutic mechanism underlying cell therapy by analyzing changes in the modification and expression of proteins 1 month post-treatment with UC-MSCs. This prospective study included 11 cirrhosis patients who received MSC injection. The laboratory indexes before and after treatment were collected to evaluate the clinical treatment effect of UC-MSCs, and the protein expression and lactylation modification in the liver were comprehensively revealed. Meanwhile, weighted gene co-expression network analysis was used to analyze the co-expression protein modules and their relationship with clinical features. The patients with liver cirrhosis showed an improvement trend after receiving UC-MSC treatment; specifically, the liver protein synthesis function was significantly improved and the coagulation function was also significantly improved. Proteomics combined with lactic acid proteomics revealed 160 lysine lactylation (Kla) sites of 119 proteins. Functional analysis showed that the lactylation-modified proteins were enriched in the pathway of glucose and other substances' metabolism, and many key enzymes of glycolysis and gluconeogenesis were lactated. UC-MSC therapy has a certain clinical effect in the treatment of liver cirrhosis and may act by regulating material metabolism, because the lactylation protein points to energy metabolism.

Targeting BCAA metabolism to potentiate metformin's therapeutic efficacy in the treatment of diabetes in mice.

An increasing body of evidence has shown that the catabolism of branched-chain amino acids (BCAAs; leucine, isoleucine and valine) is impaired in obese animals and humans, contributing to the development of insulin resistance and type 2 diabetes. Promoting BCAA catabolism benefits glycaemic control. It remains unclear whether BCAA catabolism plays a role in the therapeutic efficacy of currently used glucose-lowering drugs such as metformin. Mice were treated with vehicle or metformin (250 mg/kg per day) for more than 4 weeks to investigate the effects of metformin in vivo. In vitro, primary mouse hepatocytes and HepG2 cells were treated with 2 mmol/l metformin. The therapeutic efficacy of metformin in the treatment of type 2 diabetes was assessed in genetically obese (ob/ob) mice and high-fat-diet-induced obese (DIO) mice. Enhancing BCAA catabolism was achieved with a pharmacological agent, 3,6-dichlorobenzo[b]thiophene-2-carboxylic acid (BT2). The ob/ob mice were treated with a low-BCAA diet or intermittent protein restriction (IPR) to reduce BCAA nutritional intake. Metformin unexpectedly inhibited the catabolism of BCAAs in obese mice, resulting in an elevation of BCAA abundance. AMP-activated protein kinase (AMPK) mediated the impact of metformin on BCAA catabolism in hepatocytes. Importantly, enhancing BCAA catabolism via a pharmacological agent BT2 significantly potentiated the glucose-lowering effect of metformin while decreasing circulating BCAA levels in ob/ob and DIO mice. Similar outcomes were achieved by a nutritional approach of reducing BCAA intake. IPR also effectively reduced the circulating BCAA abundance and enhanced metformin's glucose-lowering effect in ob/ob mice. BT2 and IPR treatments reduced the expression of fructose-1,6-bisphosphatase 1, a rate-limiting enzyme in gluconeogenesis, in the kidney but not liver, indicating the involvement of renal gluconeogenesis. Metformin self-limits its therapeutic efficacy in the treatment of type 2 diabetes by triggering the suppression of BCAA catabolism. Enhancing BCAA catabolism pharmacologically or reducing BCAA intake nutritionally potentiates the glucose-lowering effect of metformin. These data highlight the nutritional impact of protein on metformin's therapeutic efficacy and provide new strategies targeting BCAA metabolism to improve metformin's effects on the clinical outcome in diabetes.

Regulation of glucose homeostasis in Macrobrachium rosenbergii: Effects of glucose load on glucose metabolism and hormonal response

The aim of this study was to assess the glucose tolerance of the giant freshwater prawn, Macrobrachium rosenbergii, and investigate the underlying mechanisms that regulate glucose homeostasis. A glucose tolerance test was conducted by fasting the giant freshwater prawns for 24 h, followed by an intraperitoneal injection of 1 mg of glucose per gram of body weight. The content of glucose, trehalose (disaccharide composed of two glucose molecules), glycogen, triglyceride, and protein levels in the plasma, hepatopancreas and muscle, as well as the transcriptional level of metabolism-related genes, were examined. Besides, the potential damage caused by glucose injection was evaluated by histological examination. Results showed that plasma glucose and trehalose levels peaked at 0.5 and 1 h after injection, respectively, and returned to baseline levels between 2 and 4 h, indicating a rapid clearance of exogenous glucose. The content of trehalose, glycogen, and triglyceride in both the hepatopancreas and muscle significantly increased at a relatively high speed after the glucose load, while the protein levels remained unchanged. Transcriptional levels of a rate-limiting enzyme in gluconeogenesis (phosphoenolpyruvate carboxykinase), and several enzymes involved in catabolism of trehalose (trehalase), glycogen (glycogen debranching enzyme), and triglyceride (adipose triglyceride lipase), were observed to be downregulated immediately following the glucose injection. In contrast, glycolysis and anabolism were stimulated, as indicated by increased mRNA levels of glucokinase, trehalose-6-phosphate synthase, glycogen branching enzyme, and diacylglycerol acyltransferase. Furthermore, the glucose injection decreased the expression of crustacean hyperglycemic hormone (CHH) and increased the expression of insulin-like peptide 1 (ILP1), while insulin-like peptide 2 (ILP2) expression remained unchanged. No noticeable histopathological damage to the hepatopancreas and muscle was observed after glucose injection. These findings suggest that M. rosenbergii demonstrated a rapid clearance of exogenous glucose. A glucose load may induce the expression of ILP1, stimulate glycolysis and the conversion of glucose to trehalose, glycogen, and triglyceride, while decreasing the expression of CHH and inhibiting gluconeogenesis to aid in the efficient regulation of glucose homeostasis in M. rosenbergii.

Growth, biochemical indices and transcriptomic profile of Chinese mitten crab (Eriocheir sinensis) respond to different ratios of dietary carbohydrates to lipids

IntroductionAlthough carbohydrates and lipids are important energy substances for Chinese mitten crab (Eriocheir sinensis), little is known about their synergistic effect on the growth, energy utilization characteristics and mechanisms involved in this process.MethodsA 58-d feeding experiment was conducted to investigate the effects of dietary carbohydrate to lipid ratio (C/L) on the growth performance, biochemical indices, and metabolism-related differential gene expression of juvenile E. sinensis in both intermolt (InM) and premolt (PrM) stages. Five experimental diets were formulated with increasing dietary C/L (1.34, 2.39, 3.59, 5.52 and 9.42).ResultsThe results showed that the weight growth rate of juvenile E. sinensis was highest in dietary C/L3.59 group, which was significantly higher than that in the other groups. As dietary C/L increased, the hepatic glycogen contents increased, but triglyceride contents decreased in the hepatopancreas of E. sinensis in the InM. In both two molting stages, the activities of glycogen synthase and fatty acid synthase paralleled with their contents, respectively. Crabs in the InM showed higher contents of triglyceride and the activities of glycolytic rate-limiting enzymes but lower contents of hepatic glycogen than those in the PrM, especially in the C/L 1.34 and C/L 3.59 groups. In all dietary groups, the activities and transcription of gluconeogenesis and fatty acid synthesis related enzymes were significantly higher in the InM than those in the PrM. KEGG analysis showed that differential genes were enriched in fatty acid biosynthesis, fatty acid metabolism, oxidative phosphorylation pathway, pentose phosphate pathway, pyruvate metabolism and steroid biosynthesis between different dietary groups and molting stages.DiscussionTo conclude, the optimal dietary C/L was estimated to be 3.59 for juvenile E. sinensis based on the survival and growth performance. Compared to PrM, E. sinensis in the InM was more active in the carbohydrate metabolism (glycolysis and gluconeogenesis) and fatty acid synthesis, with more triglyceride and less glycogen accumulated in the hepatopancreas.This study could contribute to better understanding the carbohydrate and lipid metabolism between different molting stages, and optimizing the precise feed formulation for juvenile E. sinensis.

#4425 EZH2 PROMOTES RENAL INTERSTITIAL FIBROSIS THROUGH DOWNREGULATION OF PHOSPHOENOLPYRUVATE CARBOXYKINASE 1 MEDIATED GLUCONEOGENESIS

Abstract Background and Aims Renal fibrosis is the common pathological pathway of various chronic kidney diseases progressing to the end stage of renal failure. The methyltransferase enhancer of zeste homolog 2 (EZH2) has been identified as a therapeutic target to inhibit renal interstitial fibrosis. However, the mechanism underlying the role of EZH2 in renal fibrosis is not completely understood. Method Unilateral ureteral obstruction (UUO), unilateral ischemia-reperfusion injury (UIRI) mouse models were established. PCR, cleavage under targets and tagmentation (CUT&Tag) and Western blotting was performed to evaluate the expression of EZH2 and phosphoenolpyruvate carboxykinase 1 (PCK1). Results By using EZH2 inhibitor 3-DZNeP and Ezh2 conditional knockout mice, we confirmed the pro-fibrotic effect of EZH2 in unilateral ureteral obstruction (UUO). Through RNA sequence and cleavage under targets and tagmentation (CUT&Tag) sequence analysis, we found that the phosphoenolpyruvate carboxykinase 1 (PCK1), a critical enzyme in gluconeogenesis, is negatively regulated by EZH2 in fibrotic kidneys, which was further confirmed by quantitative PCR, CUT&Tag and Western blotting. We further showed that deletion or inhibition of EZH2 inhibited renal fibrosis and enhanced PCK1 expression and activity in unilateral ischemia-reperfusion injury (UIRI) and folic acid induced mouse nephropathy. Moreover, the dysregulated production of renal glucose and lactate in mouse UUO kidneys was restored after EZH2 inhibition by 3-DZNeP. Finally, inhibition of PCK1 by 3-mercaptopropionic acid (3-MPA) abrogated the anti-fibrotic effect of 3-DZNeP in UUO kidneys. Conclusion We conclude that EZH2 promotes renal interstitial fibrosis through inhibition of PCK1 mediated gluconeogenesis.

Fibroblast growth factor 15, induced by elevated bile acids, mediates the improvement of hepatic glucose metabolism after sleeve gastrectomy.

Fibroblast growth factor (FGF) 15/19, which is expressed in and secreted from the distal ileum, can regulate hepatic glucose metabolism in an endocrine manner. The levels of both bile acids (BAs) and FGF15/19 are elevated after bariatric surgery. However, it is unclear whether the increase in FGF15/19 is induced by BAs. Moreover, it remains to be understood whether FGF15/19 elevations contribute to improvements in hepatic glucose metabolism after bariatric surgery. To investigate the mechanism of improvement of hepatic glucose metabolism by elevated BAs after sleeve gastrectomy (SG). By calculating and comparing the changes of body weight after SG with SHAM group, we examined the weight-loss effect of SG. The oral glucose tolerance test (OGTT) test and area under the curve of OGTT curves were used to assess the anti-diabetic effects of SG. By detecting the glycogen content, expression and activity of glycogen synthase as well as the glucose-6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase (Pepck), we evaluated the hepatic glycogen content and gluconeogenesis activity. We examined the levels of total BA (TBA) together with the farnesoid X receptor (FXR)-agonistic BA subspecies in systemic serum and portal vein at week 12 post-surgery. Then the histological expression of ileal FXR and FGF15 and hepatic FGF receptor 4 (FGFR4) with its corresponding signal pathways involved in glucose metabolism were detected. After surgery, food intake and body weight gain of SG group was decreased compare with the SHAM group. The hepatic glycogen content and glycogen synthase activity was significantly stimulated after SG, while the expression of the key enzyme for hepatic gluconeogenesis: G6Pase and Pepck, were depressed. TBA levels in serum and portal vein were both elevated after SG, the FXR-agonistic BA subspecies: Chenodeoxycholic acid (CDCA), lithocholic acid (LCA) in serum and CDCA, DCA, LCA in portal vein were all higher in SG group than that in SHAM group. Consequently, the ileal expression of FXR and FGF15 were also advanced in SG group. Moreover, the hepatic expression of FGFR4 was stimulated in SG-operated rats. As a result, the activity of its corresponding pathway for glycogen synthesis: FGFR4-Ras-extracellular signal regulated kinase pathway was stimulated, while the corresponding pathway for hepatic gluconeogenesis: FGFR4- cAMP regulatory element-binding protein- peroxisome proliferator-activated receptor γ coactivator-1α pathway was suppressed. Elevated BAs after SG induced FGF15 expression in distal ileum by activating their receptor FXR. Furthermore, the promoted FGF15 partly mediated the improving effects on hepatic glucose metabolism of SG.

A multi-omics investigation of tacrolimus off-target effects on a proximal tubule cell-line

IntroductionTacrolimus, an immunosuppressive drug prescribed to a majority of organ transplant recipients is nephrotoxic, through still unclear mechanisms. This study on a lineage of proximal tubular cells using a multi-omics approach aims to detect off-target pathways modulated by tacrolimus that can explain its nephrotoxicity. MethodsLLC-PK1 cells were exposed to 5 µM of tacrolimus for 24 h in order to saturate its therapeutic target FKBP12 and other high-affine FKBPs and favour its binding to less affine targets. Intracellular proteins and metabolites, and extracellular metabolites were extracted and analysed by LC-MS/MS. The transcriptional expression of the dysregulated proteins PCK-1, as well as of the other gluconeogenesis-limiting enzymes FBP1 and FBP2, was measured using RT-qPCR. Cell viability with this concentration of tacrolimus was further checked until 72 h. ResultsIn our cell model of acute exposure to a high concentration of tacrolimus, different metabolic pathways were impacted including those of arginine (e.g., citrulline, ornithine) (p < 0.0001), amino acids (e.g., valine, isoleucine, aspartic acid) (p < 0.0001) and pyrimidine (p < 0.01). In addition, it induced oxidative stress (p < 0.01) as shown by a decrease in total cell glutathione quantity. It impacted cell energy through an increase in Krebs cycle intermediates (e.g., citrate, aconitate, fumarate) (p < 0.01) and down-regulation of PCK-1 (p < 0.05) and FPB1 (p < 0.01), which are key enzymes in gluconeogenesis and acid-base balance control. DiscussionThe variations found using a multi-omics pharmacological approach clearly point towards a dysregulation of energy production and decreased gluconeogenesis, a hallmark of chronic kidney disease which may also be an important toxicity pathway of tacrolimus.

PCK1 activates oncogenic autophagy via down-regulation Serine phosphorylation of UBAP2L and antagonizes colorectal cancer growth

Phosphoenolpyruvate carboxykinase 1 (PCK1) is the rate-limiting enzyme in gluconeogenesis. PCK1 is considered an anti-oncogene in several human cancers. In this study, we aimed to determine the functions of PCK1 in colorectal cancer (CRC). PCK1 expression in CRC tissues was tested by western blot and immunohistochemistry analyses and associations of PCK1 level with clinicopathological characteristics and disease survival evaluated. Further, we studied the effect of PCK1 on CRC cell proliferation and the underlying mechanisms. Our results show that PCK1 is expressed at significantly lower levels in CRC than in control tissues. High PCK1 expression was correlated with smaller tumor diameter and less bowel wall invasion (T stage). Overexpression and knockdown experiments demonstrated that PCK1 inhibits CRC cell growth both in vitro and in vivo. Mechanistically, PCK1 antagonizes CRC growth via inactivating UBAP2L phosphorylation at serine 454 and enhancing autophagy. Overall, our findings reveal a novel molecular mechanism involving PCK1 and autophagy, and highlight PCK1 as a promising candidate therapeutic target in CRC.

Douchi Peptides Vy and Sfllr Improve Glucose Homeostasis and Gut Dysbacteriosis In High-Fat Diet-Induced Insulin Resistant Mice.

Two peptides VY (Val-Tyr) and SFLLR (Ser-Phe-Leu-Leu-Arg) were recently identified from soy-fermented douchi with hypoglycemic activity in cells. The study aimed to understand their potential effects on glucose metabolism and insulin sensitivity as well as their mechanisms of action in a high-fat diet (HFD) induced insulin resistant model. C57BL/6 mice were fed HFD for 8 weeks, followed by peptide supplementation (doses: 10 and 50 mg/kg body weight) for 8 weeks. Peptides supplementation, especially SFLLR, reduced body weight gain, insulin resistance, hyperglycemia, inflammation, liver injury, and lipid accumulation. In both muscle and liver, both peptides activated glycogen synthase (GS), the key enzyme for glycogen synthesis, and also inhibited phosphoenolpyruvate carboxykinase (PEPCK) and glucose 6-phosphatase (G6PC), two rate-limiting enzymes for gluconeogenesis, via insulin and AMPK (5' adenosine monophosphate-activated protein kinase) signalling pathways. Furthermore, VY and SFLLR supplementation reversed HFD-induced gut dysbacteriosis by decreasing the abundance of Enterococcus, Oscillibacter, and Deferribacter, and also increased the abundances of Alistipes, Lactobacillus, Faecalibaculum, Akkermansia, and Bifidobacterium (usually beneficial in the intestine). Our study revealed the potential applications of peptides VY and SFLLR as a diet-based strategy for the prevention of type 2 diabetes. This article is protected by copyright. All rights reserved.

Hepatic but not Intestinal FBP1 Is Required for Fructose Metabolism and Tolerance.

Fructose intolerance in mammals is caused by defects in fructose absorption and metabolism. Fructose-1,6-bisphosphatase 1 (FBP1) is a key enzyme in gluconeogenesis, and its deficiency results in hypoglycemia as well as intolerance to fructose. However, the mechanism about fructose intolerance caused by FBP1 deficiency has not been fully elucidated. Here, we demonstrate that hepatic but not intestinal FBP1 is required for fructose metabolism and tolerance. We generated inducible knockout mouse models specifically lacking FBP1 in adult intestine or liver. Intestine-specific deletion of Fbp1 in adult mice does not compromise fructose tolerance, as evidenced by no significant body weight loss, food intake reduction, or morphological changes of the small intestine during 4 weeks of exposure to a high-fructose diet. By contrast, liver-specific deletion of Fbp1 in adult mice leads to fructose intolerance, as manifested by substantial weight loss, hepatomegaly, and liver injury after exposure to a high-fructose diet. Notably, the fructose metabolite fructose-1-phosphate is accumulated in FBP1-deficient liver after fructose challenge, which indicates a defect of fructolysis, probably due to competitive inhibition by fructose-1,6-bisphosphate and may account for the fructose intolerance. In conclusion, these data have clarified the essential role of hepatic but not intestinal FBP1 in fructose metabolism and tolerance.

Gluconeogenesis in the kidney: in health and in chronic kidney disease.

Chronic kidney disease (CKD) is a global health issue with increasing prevalence. Despite large improvements in current therapies, slowing CKD progression remains a challenge. A better understanding of renal pathophysiology is needed to offer new therapeutic targets. The role of metabolism alterations and mitochondrial dysfunction in tubular cells is increasingly recognized in CKD progression. In proximal tubular cells, CKD progression is associated with a switch from fatty acid oxidation to glycolysis. Glucose synthesis through gluconeogenesis is one of the principal physiological functions of the kidney. Loss of tubular gluconeogenesis in a stage-dependent manner is a key feature of CKD and contributes to systemic and possibly local metabolic complications. The local consequences observed may be related to an accumulation of precursors, such as glycogen, but also to the various physiological functions of the gluconeogenesis enzymes. The basic features of metabolism in proximal tubular cells and their modifications during CKD will be reviewed. The metabolic modifications and their influence on kidney disease will be described, as well as the local and systemic consequences. Finally, therapeutic interventions will be discussed.

Xanthosine, a purine glycoside mediates hepatic glucose homeostasis through inhibition of gluconeogenesis and activation of glycogenesis via regulating the AMPK/ FoxO1/AKT/GSK3β signaling cascade

Type 2 Diabetes Mellitus (T2DM) is characterized by hepatic insulin resistance, which results in increased glucose production and reduced glycogen storage in the liver. There is no previous study in the literature that has explored the role of Xanthosine in hepatic insulin resistance. Moreover, mechanistic explanation for the beneficial effects of Xanthosine in lowering glucose production in diabetes is yet to be determined. This study for the first time investigated the beneficial effects of Tribulus terrestris (TT) and its active constituent, Xanthosine on gluconeogenesis and glycogenesis in Free Fatty Acid (FFA)-induced CC1 hepatocytes and streptozotocin (STZ)-induced Wistar rats. Xanthosine enhanced glucose uptake and decreased glucose production through phosphorylation of AMP-activated protein kinase (AMPK) and forkhead box transcription factor O1 (FoxO1), and downregulation of two rate limiting enzymes of gluconeogenesis, phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) expression in FFA-induced CC1 cells. Xanthosine also prevented FFA-induced decreases in the phosphorylation of AKT/Protein kinase B, glycogen synthase kinase-3β (GSK3β), and increased glycogen synthase (GS) phosphorylation to increase the glycogen content in the hepatocytes. Moreover, in STZ-induced diabetic rats, oral administration of TT n-butanol fraction (TTBF) enriched with compound Xanthosine (10, 50 & 100 mg/kg body weight) improved insulin sensitivity, reduced fasting blood glucose levels, improved glucose homeostasis by reducing gluconeogenesis via AMPK/FoxO1-mediated PEPCK and G6Pase down-regulation and increasing glycogenesis via AKT/GSK3β-mediated GS activation. Overall, Xanthosine may be developed further for treating insulin resistance and hyperglycemia in T2DM.

Cranberry Proanthocyanidins as a Therapeutic Strategy to Curb Metabolic Syndrome and Fatty Liver-Associated Disorders.

While the prevalence of metabolic syndrome (MetS) is steadily increasing worldwide, no optimal pharmacotherapy is readily available to address its multifaceted risk factors and halt its complications. This growing challenge mandates the development of other future curative directions. The purpose of the present study is to investigate the efficacy of cranberry proanthocyanidins (PACs) in improving MetS pathological conditions and liver complications; C57BL/6J mice were fed either a standard chow or a high fat/high sucrose (HFHS) diet with and without PACs (200 mg/kg), delivered by daily gavage for 12 weeks. Our results show that PACs lowered HFHS-induced obesity, insulin resistance, and hyperlipidemia. In conjunction, PACs lessened circulatory markers of oxidative stress (OxS) and inflammation. Similarly, the anti-oxidative and anti-inflammatory capacities of PACs were noted in the liver in association with improved hepatic steatosis. Inhibition of lipogenesis and stimulation of beta-oxidation could account for PACs-mediated decline of fatty liver as evidenced not only by the expression of rate-limiting enzymes but also by the status of AMPKα (the key sensor of cellular energy) and the powerful transcription factors (PPARα, PGC1α, SREBP1c, ChREBP). Likewise, treatment with PACs resulted in the downregulation of critical enzymes of liver gluconeogenesis, a process contributing to increased rates of glucose production in type 2 diabetes. Our findings demonstrate that PACs prevented obesity and improved insulin resistance likely via suppression of OxS and inflammation while diminishing hyperlipidemia and fatty liver disease, as clear evidence for their strength of fighting the cluster of MetS abnormalities.

Protein Kinase CK2 Contributes to Glucose Homeostasis by Targeting Fructose-1,6-Bisphosphatase 1

Glucose homeostasis is of critical importance for the survival of organisms. It is under hormonal control and often coordinated by the action of kinases and phosphatases. We have previously shown that CK2 regulates insulin production and secretion in pancreatic β-cells. In order to shed more light on the CK2-regulated network of glucose homeostasis, in the present study, a qRT-PCR array was carried out with 84 diabetes-associated genes. After inhibition of CK2, fructose-1,6-bisphosphatase 1 (FBP1) showed a significant lower gene expression. Moreover, FBP1 activity was down-regulated. Being a central enzyme of gluconeogenesis, the secretion of glucose was decreased as well. Thus, FBP1 is a new factor in the CK2-regulated network implicated in carbohydrate metabolism control.

Metformin can mitigate skeletal dysplasia caused by Pck2 deficiency

As an important enzyme for gluconeogenesis, mitochondrial phosphoenolpyruvate carboxykinase (PCK2) has further complex functions beyond regulation of glucose metabolism. Here, we report that conditional knockout of Pck2 in osteoblasts results in a pathological phenotype manifested as craniofacial malformation, long bone loss, and marrow adipocyte accumulation. Ablation of Pck2 alters the metabolic pathways of developing bone, particularly fatty acid metabolism. However, metformin treatment can mitigate skeletal dysplasia of embryonic and postnatal heterozygous knockout mice, at least partly via the AMPK signaling pathway. Collectively, these data illustrate that PCK2 is pivotal for bone development and metabolic homeostasis, and suggest that regulation of metformin-mediated signaling could provide a novel and practical strategy for treating metabolic skeletal dysfunction.

Betaine Reduces Lipid Anabolism and Promotes Lipid Transport in Mice Fed a High-Fat Diet by Influencing Intestinal Protein Expression.

Betaine is more efficient than choline and methionine methyl donors, as it can increase nitrogen storage, promote fat mobilisation and fatty acid oxidation and change body fat content and distribution. Lipid is absorbed primarily in the small intestine after consumption, which is also the basis of lipid metabolism. This study was conducted to establish a mouse model of obesity in Kunming mice of the same age and similar body weight, and to assess the effect of betaine on the intestinal protein expression profile of mice using a proteomic approach. Analysis showed that betaine supplementation reversed the reduction in expression of proteins related to lipid metabolism and transport in the intestine of mice induced by a high-fat diet (HFD). For example, the addition of betaine resulted in a significant upregulation of microsomal triglyceride transfer protein (Mttp), apolipoprotein A-IV (Apoa4), fatty-acid-binding protein 1 (Fabp1) and fatty-acid-binding protein 2 (Fabp2) expression compared to the HFD group (p < 0.05), which exhibited accelerated lipid absorption and then translocation from the intestine into the body’s circulation, in addition to a significant increase in Acetyl-CoA acyltransferase (Acaa1a) protein expression, hastening lipid metabolism in the intestine (p < 0.05). Simultaneously, a significant reduction in protein expression of alpha-enolase 1 (Eno1) as the key enzyme for gluconeogenesis in mice in the betaine-supplemented group resulted in a reduction in lipid synthesis in the intestine (p < 0.05). These findings provide useful information for understanding the changes in the protein profile of the small intestine in response to betaine supplementation and the potential physiological regulation of diets’ nutrient absorption.

The mechanistic target of rapamycin complex 1 pathway involved in hepatic gluconeogenesis through peroxisome-proliferator-activated receptor γ coactivator-1α.

Cattle can efficiently perform de novo generation of glucose through hepatic gluconeogenesis to meet post-weaning glucose demand. Substantial evidence points to cattle and non-ruminant animals being characterized by phylogenetic features in terms of their differing capacity for hepatic gluconeogenesis, a process that is highly efficient in cattle yet the underlying mechanism remains unclear. Here we used a variety of transcriptome data, as well as tissue and cell-based methods to uncover the mechanisms of high-efficiency hepatic gluconeogenesis in cattle. We showed that cattle can efficiently convert propionate into pyruvate, at least partly, via high expression of acyl-CoA synthetase short-chain family member 1 (ACSS1), propionyl-CoA carboxylase alpha chain (PCCA), methylmalonyl-CoA epimerase (MCEE), methylmalonyl-CoA mutase (MMUT), and succinate-CoA ligase (SUCLG2) genes in the liver (P < 0.01). Moreover, higher expression of the rate-limiting enzymes of gluconeogenesis, such as phosphoenolpyruvate carboxykinase (PCK) and fructose 1,6-bisphosphatase (FBP), ensures the efficient operation of hepatic gluconeogenesis in cattle (P < 0.01). Mechanistically, we found that cattle liver exhibits highly active mechanistic target of rapamycin complex 1 (mTORC1), and the expressions of PCCA, MMUT, SUCLG2, PCK, and FBP genes are regulated by the activation of mTORC1 (P < 0.001). Finally, our results showed that mTORC1 promotes hepatic gluconeogenesis in a peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) dependent manner. Collectively, our results not only revealed an important mechanism responsible for the quantitative differences in the efficiency of hepatic gluconeogenesis in cattle versus non-ruminant animals, but also established that mTORC1 is indeed involved in the regulation of hepatic gluconeogenesis through PGC-1α. These results provide a novel potential insight into promoting hepatic gluconeogenesis through activated mTORC1 in both ruminants and mammals.

FBP1 /miR-24-1/enhancer axis activation blocks renal cell carcinoma progression via Warburg effect.

Warburg effect is a pivotal hallmark of cancers and appears prevalently in renal cell carcinoma (RCC). FBP1 plays a negative role in Warburg effect as a rate-limiting enzyme in gluconeogenesis, yet its mechanism in RCC remains to be further characterized. Herein, we revealed that FBP1 was downregulated in RCC tissue samples and was related to the poor survival rate of RCC. Strikingly, miR-24-1 whose DNA locus is overlapped with enhancer region chr9:95084940-95087024 was closely linked with the depletion of FBP1 in RCC. Of note, miRNAs like miR-24-1 whose DNA loci are enriched with H3K27ac and H3K4me1 modifications are belonging to nuclear activating miRNAs (NamiRNAs), which surprisingly upregulate target genes in RCC through enhancer beyond the conventional role of repressing target gene expression. Moreover, miR-24-1 reactivated the expression of FBP1 to suppress Warburg effect in RCC cells, and subsequently inhibited proliferation and metastasis of RCC cells. In mechanism, the activating role of miR-24-1 was dependent on enhancer integrity by dual luciferase reporter assay and CRISPR/Cas9 system. Ultimately, animal assay in vivo validated the suppressive function of FBP1 on 786-O and ACHN cells. Collectively, the current study highlighted that activation of FBP1 by enhancer-overlapped miR-24-1 is capable of contributing to Warburg effect repression through which RCC progression is robustly blocked, providing an alternative mechanism for RCC development and as well implying a potential clue for RCC treatment strategy.

An Iranian Patient with Fructose 1,6 Bisphosphatase Deficiency: A Case Report

Background: Deficiency of hepatic fructose 1,6 bisphosphatase (FBPase), a key enzyme in gluconeogenesis, impairs the formation of glucose from all gluconeogenic precursors including dietary fructose. Patients present with life threatening metabolic acidosis, fasting hypoglycemia, hepatomegaly, hyperketosis, elevated lactate and uric acid level. Glycerol and glycerol-3 phosphate have been found in the urine. The diagnosis of FBPase deficiency is confirmed via DNA molecular analysis from peripheral leukocytes. The acute life threatening episodes are treated with IV glucose at high rate and bicarbonate to control hypoglycemia and acidosis.&#x0D; Case Report: Here we report a girl referred with anorexia, lethargy, recurrent vomiting, progressive respiratory distress, and hepatomegaly following respiratory viral infection. She also had a history of twice similar attacks but milder than previous episodes. The test results showed hypoglycemia and severe metabolic acidosis. Despite proper treatment, the patient died of pulmonary edema following a respiratory viral infection.&#x0D; Conclusion: Once FBPase deficiency has been diagnosed and adequate management introduced, its course is usually benign. Growth both psychomotor and intellectual development are unimpaired and tolerance to fasting improves with age.