Inter-islet insulin dynamics measured via controlled microfluidic stimulation

描述(申请人提供)：这项拟议的研究的目标是开发和利用新的微流控设备，并结合现有的成像方法，以阐明完整的朗格汉斯胰岛之间的细胞间信号动力学。人们对协调胰腺内多个胰岛之间的振荡的可能机制知之甚少，但在整个动物和人类的胰腺中观察到的全球脉动性分泌表明这些胰岛之间存在明显的协调。由于这种脉动行为在糖尿病患者中被打乱，这些机制的阐明可以为糖尿病病情提供相当大的洞察力。在这一建议中，假设旁分泌信号在协调多个胰岛之间的振荡行为中起主要作用。由于典型的胰岛直径在100-200微米的范围内，最常用的微流控装置中的通道尺寸被证明是分离和研究这些特殊细胞的理想选择。因此，微流控工具将被用来研究这种协调，方法是创建可以使用芯片上的阀门打开或关闭的胰岛间通信网络。在具体目标1中，将优化微流控体系结构、流量控制方法和细胞操作策略，以将锌离子浓度与单个活体胰岛的胰岛素分泌联系起来。申请人以前开发的非脉动流动控制方法将用于刺激沐浴在锌指示剂染料中的胰岛，以允许对单个胰岛的胰岛素分泌进行定量、实时成像。在特定的目标2中，将确定旁分泌信号在多个活的胰岛之间的细胞间振荡行为中的作用。在特定目标1中开发的新型微流控工具将用于将多个胰岛定位到通信网络中，并进行精确控制的非脉动刺激。这些实验将比较正常胰岛、药物改变的正常胰岛和基因操作(3IRKO)小鼠的胰岛之间的通讯，这些小鼠失去了胰岛素分泌活性，类似于II型糖尿病小鼠的胰岛。该项目是专门为利用申请人在微量分析方法学方面的专业知识提供定量成像和生物学方法方面的培训而设计的。了解这些类型的胰岛行为的机械途径的重要性怎么强调都不为过。在美国，糖尿病影响了2080万儿童和成人(占人口的7.0%)，2002年估计造成了1320亿美元的损失；这种疾病可能导致严重的并发症，如心脏病、中风、失明、肾脏疾病和神经系统疾病。

DESCRIPTION (provided by applicant): The objective of this proposed research is to develop and utilize novel microfluidic devices in concert with established imaging methods in order to elucidate intercellular signaling dynamics among intact pancreatic islets of Langerhans. Little is known about possible mechanisms that coordinate oscillations throughout multiple islets in the pancreas, but the globally pulsatile secretion that has been observed in the pancreas of whole animals and humans suggests an obvious coordination among these islets. Since this pulsatile behavior is disrupted in diabetic patients, the elucidation of these mechanisms could provide considerable insight into the diabetic condition. In this proposal, it is hypothesized that paracrine signaling plays a major role in coordinating oscillatory behavior among multiple islets. With the typical islet diameter in the range of 100-200 micrometers, the channel dimensions in most commonly used microfluidic devices prove to be ideal for isolating and studying these particular cells. Thus, microfluidic tools will be utilized to investigate this coordination by creating inter-islet communication networks that can be switched on or off using on-chip valves. In Specific Aim 1, microfluidic architectures, flow control methods, and cell manipulation strategies will be optimized to correlate zinc ion concentration with insulin secretion from single live islets. Non- pulsatile flow control methods previously developed by the applicant will be used to stimulate islets bathed in zinc-indicator dye to allow quantitative, real-time imaging of insulin secretion from individual islets. In Specific Aim 2, the role of paracrine signaling in intercellular oscillatory behavior among multiple live islets will be determined. The novel microfluidic tools developed in Specific Aim 1 will be used to position multiple islets into communication networks with precisely controlled, non-pulsatile stimulation. These experiments will compare communication among normal islets, pharmacologically altered normal islets, and islets from genetically manipulated (3IRKO mice, which have lost insulin secretory activity, resembling islets from mice with Type II diabetes. This project is specially designed to provide training in quantitative imaging and biological methods through use of the applicant's expertise in micro-analytical methodology. The importance of understanding these types of mechanistic pathways of islet behavior can not be overstated. Diabetes affects 20.8 million children and adults in the United States (7.0% of population), and cost an estimated $132 billion in 2002; the disorder can result in serious complications such as heart disease, stroke, blindness, kidney disease, and nervous system disease.