A local glucagon-like peptide 1 (GLP-1) system in human pancreatic islets
A local glucagon-like peptide 1 (GLP-1) system in human pancreatic islets
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DOI：
10.1007/s00125-012-2716-9
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发表时间：
2012-12-01
期刊：
影响因子：
8.2
通讯作者：
Dotta, F.
中科院分区：
文献类型：
--
作者：
Marchetti, P.;Lupi, R.;Dotta, F.
胰高血糖素样肽 1 (GLP-1) 是一种主要的肠降血糖素，主要由肠道 L 细胞产生，对胰腺 β 细胞具有有益作用。然而，虽然在体内只有极少量的 GLP-1 以生物活性形式到达胰腺，但一些观察结果表明 GLP-1 也可能在胰岛中产生。我们进行了全面的形态学、功能和分子研究，以评估人胰岛细胞（包括 2 型糖尿病患者的胰岛细胞）中局部 GLP-1 系统的存在和各种特征。通过免疫组织化学和共聚焦显微镜测定人胰腺中胰岛素、胰高血糖素、GLP-1、原转化酶 (PC) 1/3 和 PC2 的存在。胰岛是从非糖尿病和 2 型糖尿病供体中分离出来的。通过免疫印迹和基质辅助激光解吸电离飞行时间 (MALDI-TOF) 质谱法评估 GLP-1 蛋白丰度。通过酶解和FACS分选获得单个α和β细胞悬浮液。测量对营养物的反应中胰高血糖素和 GLP-1 的释放。共聚焦显微镜显示在 α 细胞亚群中存在 GLP-1 样和 PC1/3 免疫反应性，而在 β 细胞中未观察到 GLP-1。通过免疫印迹和质谱分析证实了分离胰岛中 GLP-1 的存在。分离的胰岛和α（但不是β）细胞组分释放GLP-1，其受到葡萄糖和精氨酸的调节。 PC1/3（也称为 PCSK1）基因在 α 细胞中表达。 2 型糖尿病患者的 GLP-1 释放量显着高于非糖尿病患者的孤立胰岛。我们已经证明，人胰岛中存在功能丰富的 GLP-1 系统，该系统存在于 α 细胞中，可能受到 2 型糖尿病的调节。
Glucagon-like peptide 1 (GLP-1) is a major incretin, mainly produced by the intestinal L cells, with beneficial actions on pancreatic beta cells. However, while in vivo only very small amounts of GLP-1 reach the pancreas in bioactive form, some observations indicate that GLP-1 may also be produced in the islets. We performed comprehensive morphological, functional and molecular studies to evaluate the presence and various features of a local GLP-1 system in human pancreatic islet cells, including those from type 2 diabetic patients.The presence of insulin, glucagon, GLP-1, proconvertase (PC) 1/3 and PC2 was determined in human pancreas by immunohistochemistry with confocal microscopy. Islets were isolated from non-diabetic and type 2 diabetic donors. GLP-1 protein abundance was evaluated by immunoblotting and matrix-assisted laser desorption-ionisation-time of flight (MALDI-TOF) mass spectrometry. Single alpha and beta cell suspensions were obtained by enzymatic dissociation and FACS sorting. Glucagon and GLP-1 release were measured in response to nutrients.Confocal microscopy showed the presence of GLP-1-like and PC1/3 immunoreactivity in subsets of alpha cells, whereas GLP-1 was not observed in beta cells. The presence of GLP-1 in isolated islets was confirmed by immunoblotting, followed by mass spectrometry. Isolated islets and alpha (but not beta) cell fractions released GLP-1, which was regulated by glucose and arginine. PC1/3 (also known as PCSK1) gene expression was shown in alpha cells. GLP-1 release was significantly higher from type 2 diabetic than from non-diabetic isolated islets.We have shown the presence of a functionally competent GLP-1 system in human pancreatic islets, which resides in alpha cells and might be modulated by type 2 diabetes.