Phantom Bursting Models and Complex Bursting Patterns in Pancreatic Islets

伯特伦 研究者和他的同事研究胰岛素分泌胰腺β细胞的行为。 这些细胞展示了广泛的复杂动态，最好借助数学建模和分析来理解。 研究人员最近开发了一种新的β细胞数学模型，该模型假定位于内质网和细胞膜之间的细胞内钙亚空间区室。 这个模型是基于最近的数据从一个合作实验室，并正在进一步发展，作为新的实验进行。 其中一个发展方向是研究胰岛和分离的β细胞中经常观察到的复杂的电脉冲模式。 通过数学建模，该分析仪确定这些复杂的节律是否是由于糖酵解的振荡-也就是说，膜驱动的爆发振荡器和内源性糖酵解振荡器的共存是否与已证实的数据以及来自合作实验室的数据一致。 一个关键的问题是，这些参与糖酵解节律的振荡器是否可以通过电耦合来同步，这是一个必要条件，因为胰岛中的β细胞是电耦合的。 最后，通过信道噪声的随机性的影响进行了研究，在单细胞和胰岛模型。 通道噪声在单个β细胞的电模式中是明显的，通过电耦合抑制这种噪声可能在胰岛中观察到的更规则和更慢的爆发模式中起关键作用。 胰岛是由β细胞组成的，其研究具有重要意义，原因有很多。 从临床角度来看，它们是正常葡萄糖稳态的关键参与者。 由于β细胞是人体内唯一制造和分泌胰岛素的细胞，它们的功能障碍会导致II型或迟发性糖尿病，这是该疾病最常见的形式。 要了解是什么导致细胞功能失常，首先必须了解它们的正常功能，这也是本研究的主要目的。 从非生物学的角度来看，β细胞是许多生物化学和细胞过程的焦点，它们在许多方面与神经元相似，但具有更复杂的生化调节机制。 因此，从β细胞的研究中获得的信息大部分转移到神经元和其他分泌细胞。 最后，从生物学的角度来看，β细胞显示出丰富的动态，只有借助数学才能真正理解。 对β细胞的建模和分析已经产生了新的数学，其中大部分可以并且正在应用于其他爆裂神经和内分泌细胞的研究。 研究者让研究生和本科生参与这个项目，为他们提供在生物科学和数学科学之间重要界面的研究机会。

Bertram The investigator and his colleagues study the behavior ofinsulin-secreting pancreatic beta-cells. These cells display awide range of complex dynamics that are best understood with theaid of mathematical modeling and analysis. The investigator hasrecently developed a new mathematical model for beta-cells thatpostulates an intracellular calcium subspace compartment locatedbetween the endoplasmic reticulum and the cell membrane. Thismodel is based on recent data from a collaborating lab, and isbeing further developed as new experiments are performed. Onedirection of development involves the investigation of complexelectrical bursting patterns that are often observed inpancreatic islets and isolated beta-cells. The investigatordetermines, through mathematical modeling, whether these complexrhythms are due to oscillations in glycolysis -- that is, whetherthe coexistence of a membrane-driven bursting oscillator and anendogenous glycolytic oscillator is consistent with the publisheddata, and with data from collaborating labs. One key questionthat is addressed is whether these oscillators involvingglycolytic rhythms can be synchronized by electrical coupling.This is a necessary condition since beta-cells are electricallycoupled in islets. Finally, the effects of stochasticity throughchannel noise are investigated in both single-cell and isletmodels. Channel noise is evident in the electrical patterns ofsingle beta-cells, and suppression of this noise throughelecrical coupling may play a key role in the more regular andslower bursting patterns observed in islets. The study of pancreatic islets, composed of beta-cells, isimportant for a number of reasons. From a clinical viewpoint,they are key players in normal glucose homeostasis. Becausebeta-cells are the only cells in the body that make and secreteinsulin, their malfunction leads to type II or late-onsetdiabetes, the most prevalent form of the disease. To understandwhat makes the cells malfunction, one must first understand theirnormal functioning, which is the primary aim of this work. From abiological viewpoint, beta-cells are of great interest as thefocal point of a number of biochemical and cellular processes.They are similar in many ways to neurons, but have more complexbiochemical regulatory mechanisms. Thus, information gained fromthe study of beta-cells largely transfers over to neurons, aswell as other secretory cells. Finally, from a mathematicalviewpoint, beta-cells display rich dynamics that can only trulybe understood with the aid of mathematics. Modeling and anlysisof beta-cells has led to new mathematics, most of which can andis being applied to the study of other bursting nerve andendocrine cells. The investigator involves graduate andundergraduate students in the project, providing them withresearch opportunities at the important interface betweenbiological and mathematical sciences.