Electrical activity-triggered glucagon-like peptide-1 secretion from primary murine L-cells
Electrical activity-triggered glucagon-like peptide-1 secretion from primary murine L-cells
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DOI：
10.1113/jphysiol.2010.198069
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发表时间：
2011-03-01
影响因子：
5.5
通讯作者：
Reimann, F.
中科院分区：
文献类型：
--
作者：
Rogers, G. J.;Tolhurst, G.;Reimann, F.
以胰高血糖素样肽1 （GLP-1）为基础的治疗方法目前广泛用于糖尿病的治疗。这种激素的生理来源是肠道l细胞，由于难以将这些细胞与邻近的上皮细胞区分开来，以及我们对其生理学的有限了解，促进分泌的努力受到了阻碍。利用最近开发的带有荧光标记l细胞的转基因小鼠，我们发现这些细胞具有电活性，并使用电压门控离子通道将营养物质的存在与GLP-1的分泌结合起来。我们提出了离子通道的识别和表征。这提高了我们对肠内分泌生理学的理解，并将支持针对肠道激素分泌的治疗方案。以胰高血糖素样肽1 （GLP-1）为基础的治疗方法目前广泛用于治疗2型糖尿病。加深我们对肠道GLP-1释放的理解可能有助于开发针对产生GLP-1的l细胞的新疗法。本研究的目的是表征原代l细胞的电活动，以及电压门控钠钙通道对GLP-1分泌的重要性。用表达胰高血糖素原启动子驱动的荧光蛋白的转基因小鼠鉴定和纯化了原代小鼠l细胞。在原代结肠培养物中鉴定出荧光l细胞，用于膜片钳记录。测定原代结肠培养物中GLP-1的分泌。采用流式细胞术纯化的l细胞，通过微阵列和定量RT-PCR检测基因表达。l细胞的电活动是由大电压门控钠电流引起的，河豚毒素对其抑制可减少基础和谷氨酰胺刺激的GLP-1分泌。通过表达分析，电压门控钙通道主要为l型、q型和t型，这与硝苯地平和ω - concontoxin MVIIC均阻断GLP-1释放的结果一致。我们观察到很大的电压依赖性钾电流，但只有一个小的铬醇敏感电流，这可能归因于KCNQ1。原代l细胞的GLP-1释放与l型和q型钙电流的电活动和激活有关。电可兴奋l细胞的概念为理解GLP-1释放如何被营养、激素和药物刺激调节提供了基础。
Non-technical summaryGlucagon like peptide 1 (GLP-1) based therapies are now widely used for the treatment of diabetes. The physiological source of the hormone is the intestinal L-cell, and attempts to boost secretion have been hindered by difficulties in distinguishing these cells from their epithelial neighbours and our consequent limited understanding of their physiology. Using recently developed transgenic mice with fluorescently labelled L-cells, we show that these cells are electrically active and use voltage-gated ion channels to couple the presence of nutrients to the secretion of GLP-1. We present the identification and characterisation of the ion channels. This improves our understanding of enteroendocrine physiology and will support therapeutic programmes aiming to target gut hormone secretion.Glucagon like peptide 1 (GLP-1) based therapies are now widely used for the treatment of type 2 diabetes. Developing our understanding of intestinal GLP-1 release may facilitate the development of new therapeutics aimed at targeting the GLP-1 producing L-cells. This study was undertaken to characterise the electrical activity of primary L-cells and the importance of voltage gated sodium and calcium channels for GLP-1 secretion. Primary murine L-cells were identified and purified using transgenic mice expressing a fluorescent protein driven by the proglucagon promoter. Fluorescent L-cells were identified within primary colonic cultures for patch clamp recordings. GLP-1 secretion was measured from primary colonic cultures. L-cells purified by flow cytometry were used to measure gene expression by microarray and quantitative RT-PCR. Electrical activity in L-cells was due to large voltage gated sodium currents, inhibition of which by tetrodotoxin reduced both basal and glutamine-stimulated GLP-1 secretion. Voltage gated calcium channels were predominantly of the L-type, Q-type and T-type, by expression analysis, consistent with the finding that GLP-1 release was blocked both by nifedipine and omega-conotoxin MVIIC. We observed large voltage-dependent potassium currents, but only a small chromanol sensitive current that might be attributable to KCNQ1. GLP-1 release from primary L-cells is linked to electrical activity and activation of L-type and Q-type calcium currents. The concept of an electrically excitable L-cell provides a basis for understanding how GLP-1 release may be modulated by nutrient, hormonal and pharmaceutical stimuli.