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ObjectiveTo explore the potential mechanism of Zuogui Jiangtang Tongmai prescription （ZJT） in the treatment of diabetes mellitus complicated with cerebral infarction （DM-CI） in rats based on the short-chain fatty acids （SCFAs）/G protein-coupled receptor 43 （GPR43）/glucagon-like peptide-1 （GLP-1）/GLP-1 receptor （GLP-1R） signaling pathway. MethodSixty SD rats were randomly divided into sham operation group， model group， low- and high-dose ZJT groups （12， 24 g·kg-1）， western medicine group （140 mg·kg-1 pioglitazone metformin tablets + 27 mg·kg-1 enteric-coated aspirin tablets）. Except for the sham operation group， all other groups were fed a high-sugar high-fat diet for 4 weeks and then subjected to intraperitoneal injection of 1% streptozotocin at 35 mg·kg-1 combined with middle cerebral artery occlusion （MCAO） to establish a DM-CI rat model. The corresponding interventions were performed with distilled water， low-dose ZJT， high-dose ZJT， pioglitazone metformin tablets， and enteric-coated aspirin tablets. After surgery， National Institutes of Health Stroke Scale （NIHSS） scoring and triphenyltetrazolium chloride （TTC） staining to measure the rat's cerebral infarct volume were carried out. Random blood glucose levels were measured， and hematoxylin-eosin （HE） staining was used to observe histopathological changes in rat brain tissues. Gas chromatography was employed to detect the content of SCFAs in the cecum contents. Enzyme-linked immunosorbent assay （ELISA） was adopted to measure serum GLP-1 level. Western blot was used to detect the protein expression of GPR43 in rat ileal tissues and GLP-1R in the ischemic brain tissues. ResultCompared with the sham operation group， the model group showed significantly increased NIHSS scores， random blood glucose levels， and cerebral infarct volumes （P<0.01）， and significantly decreased SCFAs content， GLP-1 levels， and GPR43 and GLP-1R protein expression （P<0.01）. Compared with the model group， the high-dose ZJT group and the western medicine group exhibited significantly reduced NIHSS scores， random blood glucose levels， and cerebral infarct volumes （P<0.05， P<0.01）， and significantly increased SCFAs content， GLP-1 levels， and GPR43 and GLP-1R protein expression （P<0.01）. ConclusionZJT can improve glucose metabolism disorder and reduce neurological damage in DM-CI rats， and its mechanism may be related to the increase in SCFAs content and the upregulation of the GPR43/GLP-1/GLP-1R signaling pathway.
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To develop a novel glucose-lowering biomedicine with potential benefits in the treatment of type 2 diabetes, we used the 10rolGLP-1 gene previously constructed in our laboratory and the CRISPR/Cas9 genome editing technique to create an engineered Saccharomyces cerevisiae strain. The gRNA expression vector pYES2-gRNA, the donor vector pNK1-L-PGK-10rolGLP-1-R and the Cas9 expression vector pGADT7-Cas9 were constructed and co-transformed into S. cerevisiae INVSc1 strain, with the PGK-10rolGLP-1 expressing unit specifically knocked in through homologous recombination. Finally, an S. cerevisiae strain highly expressing the 10rolGLP-1 with glucose-lowering activity was obtained. SDS-PAGE and Western blotting results confirmed that two recombinant strains of S. cerevisiae stably expressed the 10rolGLP-1 and exhibited the desired glucose-lowering property when orally administered to mice. Hypoglycemic experiment results showed that the recombinant hypoglycemic S. cerevisiae strain offered a highly hypoglycemic effect on the diabetic mouse model, and the blood glucose decline was adagio, which can avoid the dangerous consequences caused by rapid decline in blood glucose. Moreover, the body weight and other symptoms such as polyuria also improved significantly, indicating that the orally hypoglycemic S. cerevisiae strain that we constructed may develop into an effective, safe, economic, practical and ideal functional food for type 2 diabetes mellitus treatment.
Subject(s)
Mice , Animals , Saccharomyces cerevisiae/metabolism , CRISPR-Cas Systems , Glucose/metabolism , Blood Glucose/metabolism , Diabetes Mellitus, Type 2/therapy , Hypoglycemic Agents/metabolismABSTRACT
ObjectiveTo observe the pharmacodynamic effects of Cinnamomi Cortex on the incretin effect in the rat model of diabetes mellites （DM） induced by streptozotocin （STZ） and explore the underlying mechanism from glucagon-like peptide-1 （GLP-1） and dipeptidyl peptidase-4 （DPP-4）. MethodForty SD rats were randomly assigned into blank， model， sitagliptin （0.1 g·kg-1）， and low- and high-dose Cinnamomi Cortex （0.45 and 0.9 g·kg-1， respectively） groups. The DM rat model was established by a high-fat diet combined with intraperitoneal injection of 40 mg·kg-1 STZ in other groups except the blank group. The intervention lasted for 8 weeks. The status， body weight， water intake， food intake， and fasting blood glucose （FBG） of the rats were observed and determined. Hematoxylin-eosin staining was employed to reveal the pathological changes of the pancreas， and immunohistochemistry to detect the expression of glucagon in the pancreas. Biochemical assay was employed to measure the serum levels of lipid metabolism indexes such as total cholesterol （TC）， triglyceride （TG）， low-density lipoprotein （LDL）， and high-density lipoprotein （HDL）. Enzyme-linked immunosorbent assay was employed to determine the levels of glycosylated hemoglobin， insulin， glucagon， GLP-1， and glucose-dependent insulinotropic polypeptide （GIP） in rat serum， and Western blot to determine the protein levels of GLP-1 and DPP-4 in the pancreas. ResultAfter 8 weeks of intervention， the model group showed higher body weight， FBG， TC， TG， LDL， glycosylated hemoglobin， glucagon， insulin， and insulin resistance index and lower HDL， GLP-1， and GIP than the blank group （P<0.05， P<0.01）. The Cinnamomi Cortex groups showed lower body weight， FBG， TC， TG， LDL， glycosylated hemoglobin， glucagon， insulin， and insulin resistance index and higher HDL， GLP-1， and GIP than the model group （P<0.05， P<0.01）. The Cinnamomi Cortex groups showed recovered morphology of islet cells and no nucleus aggregation. Compared with the model group， the Cinnamomi Cortex groups showed declined levels of glucagon in the center of islet cells. Compared with the blank group， the model group showed up-regulated protein level of DPP-4 and down-regulated protein level of GLP-1 （P<0.01）. Compared with the model group， the high-dose Cinnamomi Cortex groups showed down-regulated protein level of DPP-4 and up-regulated protein level of GLP-1 （P<0.05）. ConclusionCinnamomi Cortex may reduce blood glucose and improve incretin effect to lower the blood glucose level by regulating DPP-4 and GLP-1 in DM rats.
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ObjectiveTo explore the effects of Gegen Qinliantang（GGQL） on the proliferation and apoptosis of intestinal epithelial cells as well as on the expression of cyclic adenosine monophosphate （cAMP）， G protein-coupled receptor 119 （GPR119）， and glucagon-like peptide-1 （GLP-1）， so as to explore its potential hypoglycemic mechanism. MethodTwenty-five Wistar rats were gavaged with GGQL at the dose of 23 g·kg-1 crude drug， twice a day， which meant that 6 mL was administered into each rat per day for preparing the GGQL-containing serum. After seven consecutive times of administration， the intestinal epithelial L （NCI-H716） cells were cultured with different concentrations （1%， 2.5%， 5%， 7.5%， and 10%） of GGQL. The cell proliferation was evaluated using cell counting kit-8 （CCK-8） and the apoptosis by flow cytometry. The GLP-1 and cAMP contents in cell supernatant were determined by enzyme-linked immunosorbent assay （ELISA）. The mRNA and protein GLP-1 and GPR119 levels were assayed by real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） and Western blot， respectively. ResultCompared with the control group， GGQL significantly reduced the proliferation of NCI-H716 cells（P<0.05）. As the GGQL concentration increased， its inhibitory effect became more obvious. GGQL at each concentration significantly promoted the apoptosis of NCI-H716 cells （P<0.05）. Compared with the control group， GGQL significantly up-regulated the expression of cAMP， GLP-1， and GPR119 （P<0.05）. The results showed that the effect of GGQL was positively correlated with its concentration， and 10% GGQL exhibited the best effect. ConclusionGGQL effectively inhibits the proliferation of NCI-H716 cells and promotes their apoptosis， and it may promote the secretion of GLP-1 by up-regulating the expression of cAMP and GPR119.
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La diabetes mellitus tipo 1 (DM1), es una enfermedad crónica caracterizada por la deficiencia de insulina debido a la pérdida de células ß pancreáticas, las alteraciones hormonales en la DM 1 no se limitan a la deficiencia de insulina; existiendo también secreción inadecuadada de glucagón en el período postprandial. Aunque el control glucémico con terapias intensivas con insulina ha reducido la incidencia de complicaciones microvascular y macrovasculares. La mayoría de las personas con DM1 tienen un control glucémico subóptimo; Por lo tanto, el uso de farmacoterapia adyuvante para mejorar el control ha sido de interés clínico. El uso de estos nuevos medicamentos brindaría la oportunidad de imitar más de cerca la fisiología pancreática normal, y contrarrestar otros mecanismos fisiopatológicos diferentes a Insulinopenia; contribuyendo a lograr un mejor control metabólico y expectativa de vida.
Type 1 diabetes mellitus (T1DM), is a chronic disease characterized by insulin deficiency due to the loss of pancreatic ß cells, the hormonal alterations in T1DM are not limited to insulin deficiency; there is also a deregulated glucagon secretion in the postprandial period. Although glycemic control with intensive therapies with insulin has reduced the incidence of microvascular and macrovascular complications, most people with T1DM1 glycemic control; therefore, the use of adjuvant pharmacotherapy to improve control has been of clinical interest. The use of these new drugs would offer the opportunity to imitate more closely the normal pancreatic physiology, and to counteract other physiopathological mechanisms different from insulinopenia; contributing to achieve better metabolic control and life expectancy.
Subject(s)
Humans , Diabetes Mellitus, Type 1/drug therapy , Hypoglycemic Agents/therapeutic use , Insulin/therapeutic use , Chemotherapy, Adjuvant , Glucagon-Like Peptide 1/therapeutic use , Sodium-Glucose Transporter 2/antagonists & inhibitors , Dipeptidyl-Peptidase IV Inhibitors/therapeutic use , Metformin/therapeutic useABSTRACT
Objective To examine the separate or combined effects of aerobic exercise and AlaGln administration on patients with type 2 diabetes mellitus(T2DM).Methods T2DM was induced in rats by feeding a high-fat diet and injecting a low dose of streptozocin.Then they were trained for 8 weeks with or without administration of alanyl glutamine(Ala-Gln).At the end of training,the content of fasting serum glucose (FBG),insulin (INS),C-peptide and glucagon like peptide-1 (GLP-1) were measured and homeostasis model assessment of insulin resistance (HOMA-IR) was calculated.Results Compared with the normal rats,significant increase was observed in the FBG concentration(P＜0.05)and HOMA-IR(P＜0.05),but significant decrease in C-peptide(P＜0.05) and GLP-1(P＜0.01) of the type 2 diabetic rats.Aerobic exercise resulted in significant decrease in the FBG and HOMA-IR levels,but significant increase in the concentration of C-peptide(P＜0.01).Ala-Gln administration reduced FBG (P＜0.05),and promoted the concentrations of serum insulin (P＜0.05),C-peptide (P＜0.01) and GLP-1(P＜0.05) significantly.The combination of aerobic exercise with Ala-Gln administration had a significant interaction on promoting serum insulin(P＜0.05),but not on decreasing FBG and HOMA-IR,or increasing C-peptide and GLP-1.Conclusion The aerobic exercise or Ala-Gln administration can significantly lower blood glucose levels by improving the impaired insulin secretion in type 2 diabetic rats,and their combination has a synergistic effect on promoting insulin secretion.
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Glucagon-like peptide-1 (GLP-1) receptors belong to the class B of G protein coupled-receptors and are expressed in pancreas,lungs,GI tract,kidneys,heart and the central nervous system.During episodes of hyperglycemia activation of GLP-1 receptors located on pancreas islet β-cells facilitates insulin release and increases insulin sensitivity to regulate blood sugar.In the central nervous system,activation of GLP-1 receptors produces neuroprotection and analgesia.In this mini-review,we have summarized our recent work:1) identification of microglial GLP-1 receptor/IL-10/ β-endorphin pathway in the spinal cord;2) discovery of the mechanisms of activation of GLP-1 receptors by which analgesic Lamiophlomis rotata and its effective ingredients iridoid glycosides produce antinociception.Our work highlight that spinal microglial GLP-1 receptor might be a human-demonstrated target for the treatment of chronic pain.
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[Summary] Type 2 diabetic patients often have risk factors such as hyperglycaemia ,dyslipidaemia , hypertension ,obesity and insulin resistance ,which increase the risks of vascular endothelial dysfunction and cardiovascular events. GLP-1 analogue and its receptor agonist ,is a novel therapy on diabetes targeting at incretin ,which can effectively control blood glucose and improve vascular endothelial dysfunction. Here we summarize the protective effect of GLP-1 analogue and its receptor agonist on vascular endothelial cell.
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The synthesized full-length hGLP-1 gene was cloned into pET-32a(+) to get the recombinant plasmid pET32-GLP-1, which could express a fusion protein containing thioredox, hexahistidine, and rhGLP-1 consecutively. The recombinant plasmid containing hGLP-1 was transformed into E.coli BL21 (DE3) and expressed by IPTG induction. The fusion protein was purified from lysates with Ni?IDA His?Bind affinity chromatography. rhGLP-1 with the purity of 90% was achieved after enterokinase digestion, Ni?IDA His?Bind affinity chromatography again, then was concentrated by ultrafiltration. The purified rhGLP-1 showed a single band on IEF gel with an isoelectric point between pH5.2 and pH5.85. ESI mass spectrometry showed that the molecular weight was 3355.0kDa as expected. rhGLP-1 was digested with trypsin followed by mass analysis and the peptide mapping produced two expected fragments with the molecular weights of 2097.7kDa and 1005.5kDa, respectively. The purified rhGLP-1 also showed obvious biological activity for both lowering plasma glucose and stimulating insulin secretion in mice.