Heterogeneity and nearest-neighbor coupling can explain small-worldness and wave properties in pancreatic islets
Heterogeneity and nearest-neighbor coupling can explain small-worldness and wave properties in pancreatic islets
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DOI：
10.1063/1.4949020
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发表时间：
2016-05-01
期刊：
影响因子：
2.9
通讯作者：
Pedersen, Morten Gram
中科院分区：
文献类型：
--
作者：
Cappon, Giacomo;Pedersen, Morten Gram
许多多细胞系统由作为合胞体工作的偶联细胞组成。朗格汉斯的胰岛是这种微器官的一个研究得很好的例子。胰岛负责分泌葡萄糖调节激素，主要是胰高血糖素和胰岛素，它们以不同的脉冲释放。为了观察胰岛内β细胞的脉动胰岛素分泌，细胞反应必须同步。现在已经很好地确定，间隙连接提供了电最近邻耦合，其允许激发波跨胰岛传播以同步β细胞群。令人惊讶的是，β细胞中钙响应的功能偶联分析显示出小世界特性，即，高度的局部耦合与一些远距离的“捷径”连接，大大减少了平均路径长度。在这里，我们调查如何这种远程功能耦合可以出现的异质性，最近邻耦合，和波传播的结果。异质结也能够解释一组实验观察到的同步和波的性质，而无需引入全或无细胞耦合和渗流理论。我们的理论结果突出了局部生物耦合如何通过异质性和波传播产生功能性小世界特性。出版社：AIP Publishing
Many multicellular systems consist of coupled cells that work as a syncytium. The pancreatic islet of Langerhans is a well-studied example of such a microorgan. The islets are responsible for secretion of glucose-regulating hormones, mainly glucagon and insulin, which are released in distinct pulses. In order to observe pulsatile insulin secretion from the beta-cells within the islets, the cellular responses must be synchronized. It is now well established that gap junctions provide the electrical nearest-neighbor coupling that allows excitation waves to spread across islets to synchronize the beta-cell population. Surprisingly, functional coupling analysis of calcium responses in beta-cells shows small-world properties, i.e., a high degree of local coupling with a few long-range "short-cut" connections that reduce the average path-length greatly. Here, we investigate how such long-range functional coupling can appear as a result of heterogeneity, nearest-neighbor coupling, and wave propagation. Heterogeneity is also able to explain a set of experimentally observed synchronization and wave properties without introducing all-or-none cell coupling and percolation theory. Our theoretical results highlight how local biological coupling can give rise to functional small-world properties via heterogeneity and wave propagation. Published by AIP Publishing.