OBJECTIVE: To investigate the effects of exendin-4 on hepatic lipid metabolism, fibrosis and oxidative stress in mice with streptozotocin (STZ)-induced diabetes and explore the underlying mechanisms. METHODS: C57BL/6J mice were fed with high-fat diet (HFD) for 4 weeks and received intraperitoneal injections of 120 mg/kg STZ to induce diabetes. After successful modeling, the mice were randomized into diabetic control group and exendin-4 treatment group (DM+E4), and in the latter group, the mice were given a daily dose of 1 nmol/kg of exendin-4 for 8 weeks. The changes in the body weight (BW) and random blood glucose (RBG) in the mice were recorded. The mRNA expressions of the genes related with liver lipid metabolism, fibrosis and oxidative stress were analyzed using RT-PCR, and the structural changes of the liver tissues were observed with HE, Sirius red and oil red O staining; the expressions of TGF-β1, Nrf2 and HO-1 proteins in the liver tissues were detected using Western blotting. RESULTS: The diabetic mice showed significantly higher RBG levels and BW with obvious lipid deposition, fibrosis and oxidative stress in the liver as compared with the normal control mice ( < 0.001). Exendin-4 treatment of the diabetic mice did not significantly lessened liver lipid deposition but obviously reduced the levels of RBG and TG ( < 0.05), lowered the expression levels of liver fibrosis-related genes TGF-β, -SMA and Col-Ⅰ ( < 0.05), increased the expression levels of the antioxidant genes Nrf2, HO-1 and GPX4 ( < 0.01), and enhanced the protein expressions of Nrf2 and HO-1 in the liver tissues ( < 0.01). CONCLUSIONS Exendin-4 improves liver fibrosis and oxidative stress in diabetic mice by activating Nrf2/HO-1 pathway without significantly reducing liver lipid deposition.
Animals ; Diabetes Mellitus, Experimental ; Exenatide ; Liver ; Liver Cirrhosis ; Mice ; Mice, Inbred C57BL ; NF-E2-Related Factor 2 ; Oxidative Stress ; Streptozocin

Glucagon-like peptide-1 (GLP-1) expression is shared by both intestinal cells and neurons of brainstem, which plays anorexigenic role on food intake. However, the exact source of physiological GLP-1 influencing food intake and pertinent mechanism of GLP-1 receptor agonists (GLP-1RA) remain unelucidated. In this study, the immediate early gene product c-Fos was chosen as the specific antigen for immunohistochemistry to show the certain areas of central nervous system (CNS) activation by the GLP-1RA. Thirty normal SD rats were randomly assigned to 3 groups, which were single intraperitoneally injected with Liraglutide (200 μg/kg), Exenatide (10 μg/kg) and saline, respectively. After injection, the amount of food intake and acute glycemic variation were assessed for comparison. The results showed that acute pharmacological dosage of GLP-1RA (Liraglutide or Exenatide) could significantly influence food intake. However, glycemic change indicated that the anorexic effect was dissociated with change in blood glucose in normal rats. Moreover, c-Fos was expressed significantly higher in major critical nuclei related to food intake in GLP-1RA groups when compared with the control group, and its expression was also found in spinal cord. The results suggested that acute administration of pharmacological doses of GLP-1 influences CNS via circulation and vagal pathways, especially on the arcuate nucleus (ARC) and the nucleus of solitary tract (NTS), and GLP-1 modulates autonomic nervous activities.
Animals ; Eating ; drug effects ; Exenatide ; pharmacology ; Glucagon-Like Peptide-1 Receptor ; agonists ; Liraglutide ; pharmacology ; Random Allocation ; Rats ; Rats, Sprague-Dawley

BACKGROUND: Obesity and insulin resistance (IR) are common features of polycystic ovary syndrome (PCOS). Metformin (MET) increases insulin sensitivity, but it is associated with unsatisfactory weight loss. The glucagon-like peptide-1 receptor agonist exenatide has been shown to reduce weight and IR in patients with diabetes. This study aimed to explore the therapeutic effects of exenatide once-weekly (QW) combined with MET on body weight, as well as metabolic and endocrinological parameters in overweight/obese women with PCOS. METHODS: Fifty overweight/obese women with PCOS diagnosed via the Rotterdam criteria were randomized to one of two treatment groups: MET (500 mg three times a day [TID]) or combination treatment (COM) (MET 500 mg TID, exenatide 2 mg QW) for 12 weeks. The primary outcomes were anthropometric changes associated with obesity, and the secondary outcomes included changes in reproductive hormone levels, glucose and lipid metabolism, and C-reactive protein. RESULTS: Forty (80%) patients completed the study. COM therapy was superior to MET monotherapy in reducing weight (P = 0.045), body mass index (BMI) (P = 0.041), and waist circumference (P = 0.023). Patients in the COM group on an average lost 3.8 ± 2.4 kg compared with 2.1 ± 3.0 kg in the MET group. In the COM group, BMI and waist circumference decreased by 1.4 ± 0.87 kg/m2 and 4.63 ± 4.42 cm compared with 0.77 ± 1.17 kg/m2 and 1.72 ± 3.07 cm in the MET group, respectively. Moreover, levels of fasting glucose, oral glucose tolerance test (OGTT) 2-h glucose, and OGTT 2-h insulin were significantly lower with COM therapy than with MET (P < 0.050). Mild and moderate gastrointestinal reactions were the most common adverse events in both groups. CONCLUSIONS: COM therapy was more effective than MET alone in reducing body weight, BMI, and waist circumference, and improving insulin sensitivity in overweight/obese women with PCOS, with acceptable short-term side effects. TRIAL REGISTRATION ClinicalTrials.gov, NCT04029272. https://clinicaltrials.gov/ct2/show/NCT04029272.
Exenatide/therapeutic use* ; Female ; Humans ; Metformin/therapeutic use* ; Obesity/drug therapy* ; Overweight ; Polycystic Ovary Syndrome/drug therapy*

OBJECTIVE: To study the effect of exendin-4(Ex-4) on the differentiation of neural stem cells(NSCs) in adult mouse subventricular zone(SVZ)and its mechanism . METHODS: NSCs in the SVZ were derived from 5-week C57BL/6J mice and the expression of nestin was detected by immunofluorescence. The cell morphology was observed after the cells treatmed with 100 nmol/L Ex-4 for 14 days.The expressions of nestin and glucagon-like peptide-1 receptor (GLP-1R) were detected by immunofluorescence. GLP-1R was knocked down by using shRNA and the study was divided into four groups: control group, Ex-4 group, GLP-1R knockdown group, GLP-1R knockdown + Ex-4 group. After treatment with 100 nmol/L Ex-4 for 14 d, β-tublin III and glial fibrillary acidic protein (GFAP) were labeled by immunofluorescence and then the proportion of β-tublin III positive cells were counted. Western blot was used to detect the activation of cAMP-response element binding protein (CREB) in NSCs. In order to further study the effects of Ex-4 on mitogen-activated protein kinase(MAPK) and phosphatidylinositol 3-hydroxy kinase (PI3K) pathways, the cells were pretreated with MAPK inhibitor U0126 at a concentration of 0.07 μmol/L for 30 min or PI3K inhibitor LY294002 at 50 μmol for 2 h, respectively. The study was divided into six groups: control group, Ex-4 group, U0126 group, U0126 + Ex-4 group, LY294002 group, LY294002 + Ex-4 group. The activation of CREB in each group was detected by Western blot. The experiment was repeated three times independently. RESULTS: NSCs were successfully extracted from SVZ of C57BL/6J mice. Immunofluorescence showed that nestin and GLP-1R were positive in NSCs. Compared with the control group, the proportion of neurons differentiated from Ex-4 group was higher. The percentage of neurons in GLP-1R knockdown + Ex-4 group was basically the same as that in control group (P＜0.01). The positive cells of beta-tublin III showed positive activation of GLP-1R and CREB. Western blot showed that CREB was significantly activated in the Ex-4 group, and knockdown of GLP-1R abolished its activation (P＜0.01). U0126 did not affect Ex-4-mediated CERB activation, and LY294002 significantly reduced Ex-4-mediated CREB activation (P＜0.01). CONCLUSION Ex-4 promotes the differentiation of NSCs into neurons in SVZ of adult mice through GLP-1R receptor, which may be achieved through PI3K/CREB pathway.
Animals ; Cell Differentiation ; Cells, Cultured ; Cyclic AMP Response Element-Binding Protein ; metabolism ; Exenatide ; pharmacology ; Gene Knockdown Techniques ; Glucagon-Like Peptide-1 Receptor ; genetics ; metabolism ; Lateral Ventricles ; cytology ; Mice ; Mice, Inbred C57BL ; Neural Stem Cells ; cytology ; Phosphatidylinositol 3-Kinases

AIM: To identify the glucose lowering ability and chronic treatment effects of a novel coumarin-glucagon-like peptide-1 (GLP-1) conjugate HJ07. METHOD: A receptor activation experiment was performed in HEK 293 cells and the glucose lowering ability was evaluated with hypoglycemic duration and glucose stabilizing tests. Chronic treatment was performed by daily injection of exendin-4, saline, and HJ07. Body weight and HbA1c were measured every week, and an intraperitoneal glucose tolerance test was performed before treatment and after treatment. RESULTS: HJ07 showed well-preserved receptor activation efficacy. The hypoglycemic duration test showed that HJ07 possessed a long-acting, glucose-lowering effect and the glucose stabilizing test showed that the antihyperglycemic activity of HJ07 was still evident at a predetermined time (12 h) prior to the glucose challenge (0 h). The long time glucose-lowering effect of HJ07 was better than native GLP-1 and exendin-4. Furthermore, once daily injection of HJ07 to db/db mice achieved long-term beneficial effects on HbA1c lowering and glucose tolerance. CONCLUSION The biological activity results of HJ07 suggest that HJ07 is a potential long-acting agent for the treatment of type 2 diabetes.
Animals ; Blood Glucose ; metabolism ; Coumarins ; pharmacology ; Diabetes Mellitus ; blood ; drug therapy ; Diabetes Mellitus, Type 2 ; drug therapy ; Exenatide ; Glucagon-Like Peptide 1 ; analogs & derivatives ; pharmacology ; therapeutic use ; Glucagon-Like Peptide-1 Receptor ; Glucose Tolerance Test ; Glycated Hemoglobin A ; metabolism ; HEK293 Cells ; Humans ; Hypoglycemic Agents ; pharmacology ; therapeutic use ; Male ; Mice, Inbred C57BL ; Mice, Knockout ; Peptides ; pharmacology ; Receptors, Glucagon ; metabolism ; Venoms ; pharmacology

OBJECTIVE: To evaluate the therapeutic effects of recombinant Exendin-4 and double-stranded adeno-associated virus (Exendin-4/dsAAV) on SD rats with type 2 diabetes (T2DM) through injecting it into submandibular gland (SG).
 METHODS: The Exendin-4/dsAAV was injected into submandibular gland of diabetic rat. The insulin and α-amylase were detected by real-time PCR at the 2nd, 4th and 8th weeks. The immunohistochemisty was used to detect the insulin contents in SG at the 8th week. The concentration of blood glucose and levels of insulin secretion were detected after pancreatectomy.
 RESULTS: The SG gland was bigger in Exendin-4/dsAAV group than that in the control group, but the changes in α-amylase were not significant. The Exendin-4 and insulin gene expression was increased in the Exendin-4/dsAAV group (P<0.05). The Exendin-4 and insulin were positive in the SG. The blood glucose was lower and insulin concentration was higher in the Exendin-4/dsAAV group than those in the control group after pancreatectomy (P<0.05), and the insulin content was also increased in the dsAAV groups.
 CONCLUSION Continuous expression of Exendin-4 in SG may improve glucose control and insulin secretion in T2DM rats through inducing expression of insulin.
Animals ; Blood Glucose ; analysis ; Dependovirus ; Diabetes Mellitus, Experimental ; therapy ; Diabetes Mellitus, Type 2 ; therapy ; Exenatide ; Genetic Therapy ; Injections ; Insulin ; chemistry ; Peptides ; genetics ; therapeutic use ; Rats ; Rats, Sprague-Dawley ; Real-Time Polymerase Chain Reaction ; Recombinant Proteins ; genetics ; therapeutic use ; Submandibular Gland ; chemistry ; Venoms ; genetics ; therapeutic use ; alpha-Amylases ; chemistry