RESUMO
BACKGROUND: Glucagon-like peptide-1 receptor (GLP-1R) and glucose-dependent insulinotropic polypeptide receptor (GIPR) co-agonists have emerged as treatment options for reversing diabetes and obesity. Here, we screened the high potency receptor-biased GLP-1R agonists via a newly designed high-throughput GLP-1R extracellular domain (ECD)-based system and demonstrated its in vitro and in vivo therapeutic characters. METHODS: Twelve 9-mer peptides (named XEL1-XEL12) which were screened from a large phage-displayed peptide library were fused to the N-terminus of GIP (3-30) to generate another twelve fusion peptides, termed XEL13-24. Using the six lysine-altered XEL17 as leading sequences, eighteen fatty chain modified fusion peptides were further assessed via in vitro GLP-1R/GIPR-based cell assay. Moreover, the acute and long-acting in vivo effects of selected candidate on diabetic db/db mice and diet-induced obesity (DIO) rats were both carefully evaluated. RESULTS: XEL17 exhibited balanced activation potency on GLP-1R/GIPR in stable cell lines, and further assessment was performed to evaluate the XEL32, a fatty chain modified XEL17 derivative. Preclinical pharmacodynamic results in diabetic db/db mice demonstrated that XEL32 held outstanding insulinotropic and glucose-lowering activities. In addition, protracted antidiabetic effects of XEL32 were also proved by the hypoglycemic test and multiple oral glucose tolerance test. Furthermore, chronic treatment of XEL32 in DIO rats exhibited outstanding beneficial effects on body weight control, fat loss, food intake control, hemoglobin A1C (HbA1C) reduction as well as the glucose tolerance. CONCLUSIONS: XEL32, as a novel GLP-1/GIP dual receptor agonist, may supply efficient glycemic control and weight loss.
Assuntos
Receptor do Peptídeo Semelhante ao Glucagon 1/metabolismo , Peptídeos/farmacologia , Receptores dos Hormônios Gastrointestinais/metabolismo , Redução de Peso/efeitos dos fármacos , Animais , Glicemia/metabolismo , China , Diabetes Mellitus/tratamento farmacológico , Receptor do Peptídeo Semelhante ao Glucagon 1/agonistas , Receptor do Peptídeo Semelhante ao Glucagon 1/efeitos dos fármacos , Teste de Tolerância a Glucose , Células HEK293 , Ensaios de Triagem em Larga Escala/métodos , Humanos , Hipoglicemiantes/farmacologia , Masculino , Camundongos , Obesidade/metabolismo , Ratos , Receptores dos Hormônios Gastrointestinais/agonistas , Receptores dos Hormônios Gastrointestinais/efeitos dos fármacosRESUMO
BACKGROUND/AIMS: The study was aimed to investigate if vitamin C could exert protective effects on development of eryptosis caused by glucose-6-phosphate dehydrogenase (G6PD) deficiency and hydrogen peroxide. METHODS: Isolated erythrocytes with different G6PD activity (normal or deficient) were divided into various groups treated by either Vitamin C or H2O2. Phosphatidylserine (PS) extroversion rate was detected by Annexin V binding. The intracellular Ca2+ concentration was detected by Fluo3-fluorescence, and western blot was used to detect the expression of apoptosis factor caspase 3. RESULTS: Compared with the blank group, the PS extroversion rate (P < 0.001), intracellular Ca2+ concentration (P < 0.001) and active caspase 3 expression level (P < 0.05) of erythrocytes significantly increased after treatment of 0.05% H2O2. Then the index of eryptosis significantly decreased after erythrocytes were treated with Vitamin C (1 mg/ml) for 30 min (all P < 0.05). The decline in erythrocytes with G6PD normal activity was more significant than those with G6PD deficiency. CONCLUSION: Vitamin C could effectively inhibit the eryptosis contributed by H2O2 oxidative stress, and the suppression on eryptosis with G6PD normal activity was more effective than that with G6PD deficiency.