Synthetic exendin-4 exhibits dose-dependent glucose-regulatory activity similar to that of native glucagon-like peptide-1(GLP-1). Moreover, exendin-4 is resistant to degradation by dipeptidyl peptidase-Ⅳ(DPP-Ⅳ) whil...Synthetic exendin-4 exhibits dose-dependent glucose-regulatory activity similar to that of native glucagon-like peptide-1(GLP-1). Moreover, exendin-4 is resistant to degradation by dipeptidyl peptidase-Ⅳ(DPP-Ⅳ) while GLP-1 is degraded by DPP-Ⅳ with a half-life of less than 2 min in mammals. In this study the stability of exendin-4 in human plasma was evaluated in vitro. Exendin-4 was incubated in plasma at 37 ℃, extracted and subsequently analyzed by using high performance liquid chromatography(HPLC). Exendin-4 was slowly broken down in plasma. Its half-life time is 9.57 h. The degradation products were identified by mass-spectrum(MS). According to natural sequence of exendin-4, we deduced that the cleavage were between the Thr5 and Phe6 bond, Phe6 and Thr7 bond, and Thr7 and Ser8 bond of the N-terminus region of the peptide, and the results of ESI-TOF-MS prove that our primary conclusion was correct.展开更多
目的 构建 、鉴定自身互补双链DNA的腺相关病毒（scAAV）重组载体，使其分泌表达Exendin-4，检测其转导效率并观察在糖尿病大鼠模型中的治疗作用。 方法 应用基因工程方法改建穿梭质粒pSSHG-CMV，插入外源性基因Exendin-...目的 构建 、鉴定自身互补双链DNA的腺相关病毒（scAAV）重组载体，使其分泌表达Exendin-4，检测其转导效率并观察在糖尿病大鼠模型中的治疗作用。 方法 应用基因工程方法改建穿梭质粒pSSHG-CMV，插入外源性基因Exendin-4，构建重组scAAV载体，感染HEK293细胞，ELISA检测转染NIH3T3细胞上清Exendin-4滴度，链佐霉素诱导20只6周龄体质量180～220 g SD成年雄性大鼠为糖尿病鼠模型，逆向注射重组scAAV于糖尿病大鼠颌下腺，检测其血糖及胰岛素分泌水平。 结果 重组scpSSHG/exn4可有效包装和复制，病毒滴度为2.5×1011pfu/mL，转染细胞上清分泌Exendin-4浓度可达到4.53 ng/mL，scAAV治疗组血糖浓度在2、4周及8周均低于对照组[分别为（639.17±27.89）vs （396.00±34.00），（657.02±39.87） vs （315.62±42.56），（215.6±24.7） vs （458.6±19.7） mg/dL]，胰岛素浓度均高于对照组[分别为（156.8±24.5） vs （535.9±35.6），（236.5±12.3） vs （495.3±18.6），（620.43±46.90） vs （381.56±21.78） pg/mL]，二者比较有显著统计学差异（P〈0.05）。 结论 成功构建重组双链腺伴病毒scAAV-Ex-4，具有高效转导能力，对糖尿病大鼠模型具有控制血糖及增加胰岛素分泌作用。展开更多
文摘Synthetic exendin-4 exhibits dose-dependent glucose-regulatory activity similar to that of native glucagon-like peptide-1(GLP-1). Moreover, exendin-4 is resistant to degradation by dipeptidyl peptidase-Ⅳ(DPP-Ⅳ) while GLP-1 is degraded by DPP-Ⅳ with a half-life of less than 2 min in mammals. In this study the stability of exendin-4 in human plasma was evaluated in vitro. Exendin-4 was incubated in plasma at 37 ℃, extracted and subsequently analyzed by using high performance liquid chromatography(HPLC). Exendin-4 was slowly broken down in plasma. Its half-life time is 9.57 h. The degradation products were identified by mass-spectrum(MS). According to natural sequence of exendin-4, we deduced that the cleavage were between the Thr5 and Phe6 bond, Phe6 and Thr7 bond, and Thr7 and Ser8 bond of the N-terminus region of the peptide, and the results of ESI-TOF-MS prove that our primary conclusion was correct.
文摘目的 构建 、鉴定自身互补双链DNA的腺相关病毒（scAAV）重组载体，使其分泌表达Exendin-4，检测其转导效率并观察在糖尿病大鼠模型中的治疗作用。 方法 应用基因工程方法改建穿梭质粒pSSHG-CMV，插入外源性基因Exendin-4，构建重组scAAV载体，感染HEK293细胞，ELISA检测转染NIH3T3细胞上清Exendin-4滴度，链佐霉素诱导20只6周龄体质量180～220 g SD成年雄性大鼠为糖尿病鼠模型，逆向注射重组scAAV于糖尿病大鼠颌下腺，检测其血糖及胰岛素分泌水平。 结果 重组scpSSHG/exn4可有效包装和复制，病毒滴度为2.5×1011pfu/mL，转染细胞上清分泌Exendin-4浓度可达到4.53 ng/mL，scAAV治疗组血糖浓度在2、4周及8周均低于对照组[分别为（639.17±27.89）vs （396.00±34.00），（657.02±39.87） vs （315.62±42.56），（215.6±24.7） vs （458.6±19.7） mg/dL]，胰岛素浓度均高于对照组[分别为（156.8±24.5） vs （535.9±35.6），（236.5±12.3） vs （495.3±18.6），（620.43±46.90） vs （381.56±21.78） pg/mL]，二者比较有显著统计学差异（P〈0.05）。 结论 成功构建重组双链腺伴病毒scAAV-Ex-4，具有高效转导能力，对糖尿病大鼠模型具有控制血糖及增加胰岛素分泌作用。
