BACKGROUND: Previous studies have shown that 17beta-estradiol activates AMP-activated protein kinase (AMPK) in rodent muscle and C2C12 myotubes and that acute 17beta-estradiol treatment rapidly increases AMPK phosphorylation possibly through non-genomic effects but does not stimulate glucose uptake. Here, we investigated whether 24-hour 17beta-estradiol treatment stimulated glucose uptake and regulated the expression of genes associated with glucose and energy metabolism through the genomic effects of estrogen receptor (ER) in C2C12 myotubes. METHODS: C2C12 myotubes were treated with 17beta-estradiol for 24 hours, and activation of AMPK, uptake of glucose, and expression of genes encoding peroxisome proliferator-activated receptor γ coactivator 1α, carnitine palmitoyltransferase 1β, uncoupling protein 2, and glucose transporter 4 were examined. Furthermore, we investigated whether AMPK inhibitor (compound C) or estrogen receptor antagonist (ICI182.780) treatment reversed 17beta-estradiol-induced changes. RESULTS: We found that 24-hour treatment of C2C12 myotubes with 17beta-estradiol stimulated AMPK activation and glucose uptake and regulated the expression of genes associated with glucose and energy metabolism. Treatment of C2C12 myotubes with the estrogen receptor antagonist (ICI182.780) reversed 17beta-estradiol-induced AMPK activation, glucose uptake, and changes in the expression of target genes. Furthermore, treatment with the AMPK inhibitor (compound C) reversed 17beta-estradiol-induced glucose uptake and changes in the expression of target genes. CONCLUSION: Our results suggest that 17beta-estradiol stimulates AMPK activation and glucose uptake and regulates the expression of genes associated with glucose and energy metabolism in C2C12 myotubes through the genomic effects of ER.
AMP-Activated Protein Kinases ; Carnitine O-Palmitoyltransferase ; Energy Metabolism ; Estrogens ; Glucose Transport Proteins, Facilitative ; Glucose ; Muscle Fibers, Skeletal ; Peroxisomes ; Phosphorylation ; Rodentia

Nephrotic syndrome (NS) is a hypercoagulable state in which children are at risk of venous thromboembolism. A higher risk has been reported in children with steroid-resistant NS than in those with steroid-sensitive NS. The mortality rate of cerebral venous sinus thrombosis (CVST) is approximately 10% and generally results from cerebral herniation in the acute phase and an underlying disorder in the chronic phase. Our patient initially manifested as a child with massive proteinuria and generalized edema. He was treated with albumin replacement and diuretics, angiotensin-converting enzyme inhibitor, and deflazacort. Non-contrast computed tomography showed areas of hyperattenuation in the superior sagittal sinus when he complained of severe headache and vomiting. Subsequent magnetic resonance imaging revealed empty delta signs in the superior sagittal, lateral transverse, and sigmoid sinuses, suggesting acute CVST. Immediate anticoagulation therapy was started with unfractionated heparin, antithrombin III replacement, and continuous antiproteinuric treatment. The current report describes a life-threatening CVST in a child with steroid-dependent NS, initially diagnosed by contrast non-enhanced computed tomography and subsequently confirmed by contrast-enhanced magnetic resonance imaging, followed by magnetic resonance venography for recanalization, addressing successful treatment.

Gastrointestinal stromal tumor (GIST) is the most common non-epithelial neoplasm arising in the gastrointestinal tract, but this tumor is rarely seen in association with type 1 neurofibromatosis (NF-1). We report here on two cases of multiple GISTs of the small intestine that occurred in NF-1 patients. We also analyzed the mutations of c-kit exons 9, 11, 13 and 17 and the plateletderived growth factor receptor-alpha (PDGFRA) exons 12 and 18 in two GIST patients. Histologically, the NF-1-associated GISTs were similar to those of non-the NF-1 GISTs, but they characteristically revealed hyperplastic interstitial cells of Cajal around the GISTs. Immunohistochemically, these tumors showed strong co-expressions of CD117 and CD34. The molecular genetic analysis of the GISTs showed that all of the c-kit and PDGFRA exons that were analyzed in the GISTs of the two patients were the wild-type, suggesting a limited role for the c-kit and PDGFRA mutations in the tumorigenesis of NF-1-associated GISTs.
Carcinogenesis ; Exons ; Gastrointestinal Stromal Tumors* ; Gastrointestinal Tract ; Humans ; Interstitial Cells of Cajal ; Intestine, Small ; Molecular Biology ; Neurofibromatoses* ; Neurofibromatosis 1*

The upstream stimulatory factor 1 (USF1) gene has been shown to play an essential role as the cause of familial combined hyperlipidemia, and there are several association studies on the relationship between USF1 and metabolic disorders. In this study, we analyzed two single nucleotide polymorphisms in USF1 rs2073653 (306A>G) and rs2516840 (1748C>T) between the case (dyslipidemia or obesity) group and the control group in premenopausal females, postmenopausal females, and males among 275 Korean subjects. We observed a statistically significant difference in the GC haplotype between body mass index (BMI) > or =25 kg/m(2) and BMI <25 kg/m(2) groups in premenopausal females ( chi-square=4.23, p=0.04). It seems that the USF1 GC haplotype is associated with BMI in premenopausal Korean females.
Adult ; Aged ; *Body Mass Index ; Cholesterol, HDL/blood ; Female ; Genotype ; *Haplotypes ; Humans ; Linkage Disequilibrium ; Male ; Middle Aged ; *Polymorphism, Single Nucleotide ; Premenopause ; Upstream Stimulatory Factors/*genetics

BACKGROUND: The characteristic feature of pancreatic beta cells is highly developed endoplasmic reticulum (ER) due to a heavy engagement in insulin secretion. The ER serves several important function, including post-translational modification, folding, and assembly of newly synthesized secretory proteins, and its proper function is essential to cell survival. Various stress conditions can interfere with ER function. Pancreatic beta cells may be particularly vulnerable to ER stress that causes to impair insulin biosynthesis and beta cell survival through apoptosis. Glucagon like peptide-1 (GLP-1) is a new drug for treatment of type 2 diabetes and has effects on stimulation of insulin secretion and beta cell preservation. Also, it may have an antiapoptotic effect on beta cells, but detailed mechanisms are not proven. Therefore, we investigated the protective mechanism of GLP-1 in beta cells through ER stress response induced by 2-deoxy-D-glucose (2DG). METHODS: For induction of the ER stress, HIT-T15 cells (hamster beta cell line) were treated with 2DG (10 mM). Apoptosis was evaluated with MTT assay, hoechst 33342 staining and Annexin/PI flow cytometry. Expression of ER stress-related molecules was determined by real-time PCR or western blot. For blocking ER stress, we pretreated HIT-T15 cells with exendin-4 (Ex-4; GLP-1 receptor agonist) for 1 hour before stress induction. RESULTS: After induction with ER stress (2DG), beta cells were lost by apoptosis. We found that Ex-4 had a protective effect through ER stress related molecules (GRP78, GRP94, XBP-1, eIF2alpha, CHOP) modulation. Also, Ex-4 recovered the expression of insulin2 mRNA in beta cells. CONCLUSION: These results suggest that GLP-1 may protect beta cells apoptosis through ER stress modulation.
Apoptosis ; Benzimidazoles ; Blotting, Western ; Cell Survival ; Deoxyglucose ; Endoplasmic Reticulum ; Flow Cytometry ; Glucagon ; Glucagon-Like Peptide 1 ; Glucagon-Like Peptide-1 Receptor ; HSP70 Heat-Shock Proteins ; Insulin ; Insulin-Secreting Cells ; Membrane Proteins ; Peptides ; Protein Processing, Post-Translational ; Proteins ; Real-Time Polymerase Chain Reaction ; Receptors, Glucagon ; RNA, Messenger ; Venoms

Oxidative stress induced by chronic hyperglycemia in type 2 diabetes plays a crucial role in progressive loss of beta-cell mass through beta-cell apoptosis. Glucagon like peptide-1 (GLP-1) has effects on preservation of beta-cell mass and its insulin secretory function. GLP-1 possibly increases islet cell mass through stimulated proliferation from beta-cell and differentiation to beta-cell from progenitor cells. Also, it probably has an antiapoptotic effect on beta-cell, but detailed mechanisms are not proven. Therefore, we examined the protective mechanism of GLP-1 in beta-cell after induction of oxidative stress. The cell apoptosis decreased to ~50% when cells were treated with 100 microM H2O2 for up to 2 hr. After pretreatment of Ex-4, GLP-1 receptor agonist, flow cytometric analysis shows 41.7% reduction of beta-cell apoptosis. This data suggested that pretreatment of Ex-4 protect from oxidative stress-induced apoptosis. Also, Ex-4 treatment decreased GSK3beta activation, JNK phosphorylation and caspase-9, -3 activation and recovered the expression of insulin2 mRNA in beta-cell lines and secretion of insulin in human islet. These results suggest that Ex-4 may protect beta-cell apoptosis by blocking the JNK and GSK3beta mediated apoptotic pathway.
Animals ; *Apoptosis ; Caspase 3/metabolism ; Caspase 9/metabolism ; Cells, Cultured ; Cricetinae ; Flow Cytometry ; Glucagon-Like Peptide 1/pharmacology ; Glycogen Synthase Kinase 3/*metabolism ; Humans ; Hydrogen Peroxide/toxicity ; Insulin/genetics/metabolism ; Insulin-Secreting Cells/drug effects/*enzymology/metabolism ; JNK Mitogen-Activated Protein Kinases/*metabolism ; *Oxidative Stress ; Peptides/*pharmacology ; Phosphorylation ; Receptors, Glucagon/agonists/metabolism ; Signal Transduction ; Venoms/*pharmacology