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.
Mice ; Animals ; Metformin/pharmacology* ; Phosphoenolpyruvate Carboxykinase (ATP)/metabolism* ; Gluconeogenesis/genetics* ; Mice, Knockout

PURPOSE: In intrahepatic cholangiocarcinoma (iCCA), genetic characteristics on ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG)-PET scans are not yet clarified. If specific genetic characteristics were found to be related to FDG uptake in iCCA, we can predict molecular features based on the FDG uptake patterns and to distinguish different types of treatments. In this purpose, we analyzed RNA sequencing in iCCA patients to evaluate gene expression signatures associated with FDG uptake patterns. METHODS: We performed RNA sequencing of 22 cases iCCA who underwent preoperative ¹⁸F-FDG-PET, and analyzed the clinical and molecular features according to the maximum standard uptake value (SUVmax). Genes and biological pathway which are associated with SUVmax were analyzed. RESULTS: Patients with SUVmax higher than 9.0 (n = 9) had poorer disease-free survival than those with lower SUVmax (n = 13, P = 0.035). Genes related to glycolysis and gluconeogenesis, phosphorylation and cell cycle were significantly correlated with SUVmax (r ≥ 0.5). RRM2, which is related to the toxicity of Gemcitabine was positively correlated with SUVmax, and SLC27A2 which is associated with Cisplastin response was negatively correlated with SUVmax. According to the pathway analysis, cell cycle, cell division, hypoxia, inflammatory, and metabolism-related pathways were enriched in high SUVmax patients. CONCLUSION: The genomic features of gene expression and pathways can be predicted by FDG uptake features in iCCA. Patients with high FDG uptake have enriched cell cycle, metabolism and hypoxic pathways, which may lead to a more rational targeted treatment approach.
Anoxia ; Cell Cycle ; Cell Division ; Cholangiocarcinoma ; Disease-Free Survival ; Fluorodeoxyglucose F18 ; Gene Expression ; Gluconeogenesis ; Glycolysis ; Humans ; Metabolism ; Phosphorylation ; Positron-Emission Tomography ; Sequence Analysis, RNA ; Transcriptome

BACKGROUND/OBJECTIVES: Perilla frutescens (L.) Britton var. (PF) sprout is a plant of the labiate family. We have previously reported the protective effects of PF sprout extract on cytokine-induced β-cell damage. However, the mechanism of action of the PF sprout extract in type 2 diabetes (T2DM) has not been investigated. The present study was designed to study the effects of PF sprout extract and signaling mechanisms in the T2DM mice model using C57BL/KsJ-db/db (db/db) mice. MATERIALS/METHODS: Male db/db mice were orally administered PF sprout extract (100, 300, and 1,000 mg/kg of body weight) or rosiglitazone (RGZ, positive drug, 1 mg/kg of body weight) for 4 weeks. Signaling mechanisms were analyzed using liver tissues and HepG2 cells. RESULTS: The PF sprout extract (300 and 1,000 mg/kg) significantly reduced the fasting blood glucose, serum insulin, triglyceride and total cholesterol levels in db/db mice. PF sprout extract also significantly improved glucose intolerance and insulin sensitivity, decreased hepatic gluconeogenic protein expression, and ameliorated histological alterations of the pancreas and liver. Levels of phosphorylated AMP-activated protein kinase (AMPK) protein expression also increased in the liver after treatment with the extract. In addition, an increase in the phosphorylation of AMPK and decrease in the phosphoenolpyruvate carboxykinase and glucose 6-phosphatase proteins in HepG2 cells were also observed. CONCLUSIONS: Our results sugges that PF sprout displays beneficial effects in the prevention and treatment of type 2 diabetes via modulation of the AMPK pathway and inhibition of gluconeogenesis in the liver.
AMP-Activated Protein Kinases ; Animals ; Blood Glucose ; Cholesterol ; Diabetes Mellitus ; Fasting ; Gluconeogenesis ; Glucose Intolerance ; Glucose-6-Phosphatase ; Hep G2 Cells ; Humans ; Insulin ; Insulin Resistance ; Liver ; Male ; Mice ; Pancreas ; Perilla frutescens ; Perilla ; Phosphoenolpyruvate ; Phosphorylation ; Plants ; Triglycerides

ARNTL Transcription Factors ; deficiency ; metabolism ; Animals ; Cyclic AMP ; metabolism ; Gluconeogenesis ; Glucose ; biosynthesis ; HEK293 Cells ; Histone Deacetylases ; metabolism ; Humans ; Liver ; metabolism ; Mice ; Mice, Knockout

My professional journey to understand the glucose homeostasis began in the 1990s, starting from cloning of the promoter region of glucose transporter type 2 (GLUT2) gene that led us to establish research foundation of my group. When I was a graduate student, I simply thought that hyperglycemia, a typical clinical manifestation of type 2 diabetes mellitus (T2DM), could be caused by a defect in the glucose transport system in the body. Thus, if a molecular mechanism controlling glucose transport system could be understood, treatment of T2DM could be possible. In the early 70s, hyperglycemia was thought to develop primarily due to a defect in the muscle and adipose tissue; thus, muscle/adipose tissue type glucose transporter (GLUT4) became a major research interest in the diabetology. However, glucose utilization occurs not only in muscle/adipose tissue but also in liver and brain. Thus, I was interested in the hepatic glucose transport system, where glucose storage and release are the most actively occurring.
Adipogenesis ; Adipose Tissue ; Animals ; Brain ; Clone Cells* ; Cloning, Organism* ; Diabetes Mellitus, Type 2 ; Glucokinase ; Gluconeogenesis ; Glucose Transport Proteins, Facilitative* ; Glucose Transporter Type 2* ; Glucose* ; Glycolysis ; Homeostasis* ; Humans ; Hyperglycemia* ; Liver ; Promoter Regions, Genetic ; Rats* ; Transcription Factors

BACKGROUND/OBJECTIVES: This study was designed to investigate whether Gynura procumbens extract (GPE) can improve insulin sensitivity and suppress hepatic glucose production in an animal model of type 2 diabetes. MATERIALS/METHODS: C57BL/Ksj-db/db mice were divided into 3 groups, a regular diet (control), GPE, and rosiglitazone groups (0.005 g/100 g diet) and fed for 6 weeks. RESULTS: Mice supplemented with GPE showed significantly lower blood levels of glucose and glycosylated hemoglobin than diabetic control mice. Glucose and insulin tolerance test also showed the positive effect of GPE on increasing insulin sensitivity. The homeostatic index of insulin resistance was significantly lower in mice supplemented with GPE than in the diabetic control mice. In the skeletal muscle, the expression of phosphorylated AMP-activated protein kinase, pAkt substrate of 160 kDa, and PM-glucose transporter type 4 increased in mice supplemented with GPE when compared to that of the diabetic control mice. GPE also decreased the expression of glucose-6-phosphatase and phosphoenolpyruvate carboxykinase in the liver. CONCLUSIONS: These findings demonstrate that GPE might improve insulin sensitivity and inhibit gluconeogenesis in the liver.
AMP-Activated Protein Kinases ; Animals ; Diet ; Gluconeogenesis* ; Glucose ; Glucose-6-Phosphatase ; Hemoglobin A, Glycosylated ; Hyperglycemia ; Insulin Resistance* ; Insulin* ; Liver ; Mice* ; Models, Animal ; Muscle, Skeletal ; Phosphoenolpyruvate

Glucose homeostasis is tightly regulated to meet the energy requirements of the vital organs and maintain an individual's health. The liver has a major role in the control of glucose homeostasis by controlling various pathways of glucose metabolism, including glycogenesis, glycogenolysis, glycolysis and gluconeogenesis. Both the acute and chronic regulation of the enzymes involved in the pathways are required for the proper functioning of these complex interwoven systems. Allosteric control by various metabolic intermediates, as well as post-translational modifications of these metabolic enzymes constitute the acute control of these pathways, and the controlled expression of the genes encoding these enzymes is critical in mediating the longer-term regulation of these metabolic pathways. Notably, several key transcription factors are shown to be involved in the control of glucose metabolism including glycolysis and gluconeogenesis in the liver. In this review, we would like to illustrate the current understanding of glucose metabolism, with an emphasis on the transcription factors and their regulators that are involved in the chronic control of glucose homeostasis.
Gluconeogenesis ; Glucose* ; Glycogenolysis ; Glycolysis ; Homeostasis ; Liver ; Metabolic Networks and Pathways ; Metabolism* ; Negotiating ; Protein Processing, Post-Translational ; Transcription Factors

Few are familiar with the gluconeogenesis that occurs in the intestine under fasting or the influence of insulin. Recently, however, studies that revealed the function of intestinal gluconeogenesis as a regulatory process for glucose homeostasis and appetite were described. The intestine produces about 25% of total endogenous glucose during fasting and regulates energy homeostasis through communication with the brain. Glucose produced via intestinal gluconeogenesis is delivered to portal vein where periportal neural system senses glucose and sends a signal to the brain to regulate appetite and glucose homeostasis. Moreover, studies uncovered that intestinal gluconeogenesis contributes to the rapid metabolic improvements induced by gastric bypass surgery.
Appetite ; Bariatric Surgery ; Brain ; Fasting ; Gastric Bypass ; Gluconeogenesis ; Glucose* ; Homeostasis ; Insulin ; Intestines* ; Metabolism* ; Portal Vein

BACKGROUND/OBJECTIVES: Type 2 diabetes (T2D) is more frequently diagnosed and is characterized by hyperglycemia and insulin resistance. D-Xylose, a sucrase inhibitor, may be useful as a functional sugar complement to inhibit increases in blood glucose levels. The objective of this study was to investigate the anti-diabetic effects of D-xylose both in vitro and stretpozotocin (STZ)-nicotinamide (NA)-induced models in vivo. MATERIALS/METHODS: Wistar rats were divided into the following groups: (i) normal control; (ii) diabetic control; (iii) diabetic rats supplemented with a diet where 5% of the total sucrose content in the diet was replaced with D-xylose; and (iv) diabetic rats supplemented with a diet where 10% of the total sucrose content in the diet was replaced with D-xylose. These groups were maintained for two weeks. The effects of D-xylose on blood glucose levels were examined using oral glucose tolerance test, insulin secretion assays, histology of liver and pancreas tissues, and analysis of phosphoenolpyruvate carboxylase (PEPCK) expression in liver tissues of a STZ-NA-induced experimental rat model. Levels of glucose uptake and insulin secretion by differentiated C2C12 muscle cells and INS-1 pancreatic beta-cells were analyzed. RESULTS: In vivo, D-xylose supplementation significantly reduced fasting serum glucose levels (P < 0.05), it slightly reduced the area under the glucose curve, and increased insulin levels compared to the diabetic controls. D-Xylose supplementation enhanced the regeneration of pancreas tissue and improved the arrangement of hepatocytes compared to the diabetic controls. Lower levels of PEPCK were detected in the liver tissues of D-xylose-supplemented rats (P < 0.05). In vitro, both 2-NBDG uptake by C2C12 cells and insulin secretion by INS-1 cells were increased with D-xylose supplementation in a dose-dependent manner compared to treatment with glucose alone. CONCLUSIONS: In this study, D-xylose exerted anti-diabetic effects in vivo by regulating blood glucose levels via regeneration of damaged pancreas and liver tissues and regulation of PEPCK, a key rate-limiting enzyme in the process of gluconeogenesis. In vitro, D-xylose induced the uptake of glucose by muscle cells and the secretion of insulin cells by beta-cells. These mechanistic insights will facilitate the development of highly effective strategy for T2D.
Animals ; Blood Glucose* ; Complement System Proteins* ; Diet ; Fasting ; Gluconeogenesis ; Glucose Tolerance Test ; Glucose* ; Hepatocytes ; Hyperglycemia ; Insulin ; Insulin Resistance ; Liver ; Models, Animal ; Muscle Cells ; Pancreas ; Phosphoenolpyruvate Carboxylase* ; Phosphoenolpyruvate* ; Rats* ; Rats, Wistar ; Regeneration ; Sucrase ; Sucrose ; Xylose*

Glucose is essential for energy metabolism in human, especially in brain, and is a source of energy storage in the form of glycogen, fat and protein. During fetal life, the predominant source of energy is also glucose, which crosses the placenta by facilitated diffusion. There is very little endogenous glucose production under normal circumstances during fetal life. During labor, the fetus is exposed to physiological challenges that require metabolic adaptation. A healthy infant successfully manages the postnatal transition by mobilizing and using alternative. After birth, there is a rapid surge in catecholamine and glucagon levels, and a steady decrease in insulin, as blood glucose levels decline. These hormonal changes induce enzyme activities that lead to glycogenolysis and gluconeogenesis. During the first 24-48 hours of life, plasma glucose concentrations of neonates are typically lower than later in life. Distinguishing between transitional neonatal glucose regulation in normal neonates and hypoglycemia that persists or occurs for the first time beyond the first 72 hours of life is important for prompt diagnosis and treatment to avoid serious consequences.
Blood Glucose ; Brain ; Diagnosis ; Energy Metabolism ; Facilitated Diffusion ; Fetus ; Glucagon ; Gluconeogenesis ; Glucose* ; Glycogen ; Glycogenolysis ; Homeostasis* ; Humans ; Hypoglycemia ; Infant ; Infant, Newborn ; Insulin ; Parturition ; Placenta