Collaborative Research: Glial regulation of extracellular potassium as an underlying developmental mechanism for the male-female difference in pacemaker neuron firing frequency

合作研究：细胞外钾的神经胶质调节作为起搏器神经元放电频率男女差异的潜在发育机制

• 批准号: 1946910
• 负责人: Gunther Zupanc
• 金额: $ 86.24万
• 依托单位: Northeastern University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-05-01 至 2024-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1946910&HistoricalAwards=false
• 关键词: Collaborative; Research; Glial; regulation; extracellular

Differences in body form and behavior between males and females are well established in numerous species, but little is known about how they are organized during development. Electric communication by the brown ghost knifefish provides a unique opportunity for elucidating the cellular mechanisms mediating one such difference. In this weakly electric fish, males produce electric organ discharges that contain higher frequencies than those of females. The difference in discharge frequencies is controlled by the pacemaker nucleus, a neural circuit in the brainstem. Using an interdisciplinary strategy, a novel mechanistic hypothesis will be tested: astrocytes (a glial cell type) regulate (buffer) extracellular potassium ions differently in males and females, and this is responsible for the difference in their electric organ discharges. Besides providing new insights into the molecular and cellular mechanisms that underlie one specific behavior that is dimorphic between males and females, this research will also advance knowledge about the role of astrocytes in potassium buffering in the nervous system, and about the regulation of neural networks by these ions. The latter two topics play an important role in the etiology of pathological conditions involving pattern-generating neural circuits (for example, high-frequency epileptic seizures are thought to result from an impairment in potassium buffering that enhances the susceptibility for such seizures). Because of the interdisciplinary nature of this research, multiple opportunities are also provided for training students in diverse disciplines, and for curriculum development at the interface between biology and other STEM disciplines. Undergraduates will be involved in carrying out this research project via directed study courses being offered at both Northeastern University and the University of Virginia; 6-month internships will also be offered for students from Northeastern University to participate in the parts of the project conducted and at the University of Virginia. The PI and co-PI will also use parts of this research in laboratory-based upper-level undergraduate courses that they teach at their respective institutions, as well as engaging in outreach activities at local high schools and a series of STEM events for the general public. The electric organ discharge of the weakly electric fish Apteronotus leptorhynchus is a robust and well-characterized behavioral system. The frequency of these discharges is reliably different in males and females, and controlled by the neural activity of the pacemaker nucleus, an endogenous oscillator in the medulla oblongata. The neurons critically involved in the generation of these oscillations are the pacemaker and relay cells, which are enveloped by astrocytic syncytia. Significant male-female differences exist in the morphology of these astrocytes, their expression of glia-specific proteins, and the gap-junction coupling of individuals cells within the syncytium. The study will test the hypothesis that the development of the male-female difference in the frequency of the electric organ discharge is regulated through modulation by the astrocytic buffering capacity of extracellular potassium ions in the pacemaker nucleus, thereby resulting in changes in the extracellular potassium concentration and ultimately in the oscillation frequency of the neural network composed of pacemaker and relay cells. To achieve this objective, a multi- and interdisciplinary approach will be employed, including morphological and molecular analysis of the association of the astrocytic syncytium with the pacemaker and relay cells; pharmacological manipulation of glial function and examination of its behavioral effect; electrophysiological characterization of the ionic mechanisms of astrocytes that control the firing frequency of the pacemaker nucleus; and computational modeling of (i) the uptake and redistribution of potassium ions by the astrocytic syncytium, (ii) the effect of this action on the frequency of the neural oscillations of the pacemaker nucleus.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

在许多物种中，雄性和雌性之间的身体形态和行为差异已得到证实，但人们对它们在发育过程中如何组织却知之甚少。棕色鬼刀鱼的电通讯为阐明介导这种差异的细胞机制提供了独特的机会。在这种弱电鱼中，雄性产生的电器官放电频率比雌性更高。放电频率的差异由起搏器核（脑干中的神经回路）控制。使用跨学科策略，将测试一种新的机制假设：星形胶质细胞（一种神经胶质细胞类型）在男性和女性中以不同的方式调节（缓冲）细胞外钾离子，这就是其器官放电差异的原因。除了为男性和女性之间一种特定行为的分子和细胞机制提供新的见解外，这项研究还将增进对星形胶质细胞在神经系统钾缓冲中的作用以及通过以下方式调节神经网络的认识：这些离子。后两个主题在涉及模式生成神经回路的病理状况的病因学中发挥着重要作用（例如，高频癫痫发作被认为是由于钾缓冲受损而导致，从而增强了此类癫痫发作的易感性）。由于这项研究的跨学科性质，还为培养不同学科的学生以及生物学和其他 STEM 学科之间的交叉课程开发提供了多种机会。本科生将通过东北大学和弗吉尼亚大学提供的定向学习课程参与该研究项目的实施；还将为东北大学的学生提供为期 6 个月的实习机会，以参与该项目的部分内容以及在弗吉尼亚大学进行的项目。 PI 和 co-PI 还将把这项研究的一部分用于他们在各自机构教授的基于实验室的高水平本科课程，以及参与当地高中的外展活动和一系列面向公众的 STEM 活动。民众。弱电鱼Apteronotus leptorhynchus的电器官放电是一个强大且特征明确的行为系统。这些放电的频率在男性和女性中确实不同，并且由起搏核（延髓中的内源性振荡器）的神经活动控制。与这些振荡的产生密切相关的神经元是起搏器和中继细胞，它们被星形胶质细胞合胞体包裹。这些星形胶质细胞的形态、神经胶质细胞特异性蛋白的表达以及合胞体内单个细胞的间隙连接耦合存在显着的男女差异。该研究将验证这一假设，即男女器官放电频率差异的发展是通过起搏核中细胞外钾离子的星形胶质细胞缓冲能力的调节来调节的，从而导致细胞外钾浓度的变化最终影响由起搏器和中继细胞组成的神经网络的振荡频率。为了实现这一目标，将采用多学科和跨学科的方法，包括对星形细胞合胞体与起搏器和中继细胞的关系进行形态学和分子分析；神经胶质功能的药理学操作及其行为效应的检查；控制起搏器核发射频率的星形胶质细胞离子机制的电生理学特征；以及 (i) 星形细胞合胞体对钾离子的摄取和重新分布的计算模型，(ii) 这种作用对起搏器核神经振荡频率的影响。该奖项反映了 NSF 的法定使命，并被认为是值得的通过使用基金会的智力优势和更广泛的影响审查标准进行评估来获得支持。

项目成果

The effect of urethane and MS-222 anesthesia on the electric organ discharge of the weakly electric fish Apteronotus leptorhynchus

• DOI: 10.1007/s00359-022-01606-6
• 发表时间: 2023-02-17
• 期刊: JOURNAL OF COMPARATIVE PHYSIOLOGY A-NEUROETHOLOGY SENSORY NEURAL AND BEHAVIORAL PHYSIOLOGY
• 影响因子: 2.1
• 作者: Eske，Annika I.;Lehotzky，David;Zupanc，Guenther K. H.
• 通讯作者: Zupanc，Guenther K. H.

Computational modeling predicts regulation of central pattern generator oscillations by size and density of the underlying heterogenous network

• DOI: 10.1007/s10827-022-00835-7
• 发表时间: 2022-10-06
• 期刊: JOURNAL OF COMPUTATIONAL NEUROSCIENCE
• 影响因子: 1.2
• 作者: Ilies, Iulian;Zupanc, Gunther K. H.
• 通讯作者: Zupanc, Gunther K. H.

Modeling of sustained spontaneous network oscillations of a sexually dimorphic brainstem nucleus: the role of potassium equilibrium potential

• DOI: 10.1007/s10827-021-00789-2
• 发表时间: 2021-05-25
• 期刊: JOURNAL OF COMPUTATIONAL NEUROSCIENCE
• 影响因子: 1.2
• 作者: Hartman, Daniel;Lehotzky, David;Zupanc, Gunther K. H.
• 通讯作者: Zupanc, Gunther K. H.

Suggested reviewers: friends or foes?

• DOI: 10.1007/s00359-022-01553-2
• 发表时间: 2022-05-07
• 期刊: JOURNAL OF COMPARATIVE PHYSIOLOGY A-NEUROETHOLOGY SENSORY NEURAL AND BEHAVIORAL PHYSIOLOGY
• 影响因子: 2.1
• 作者: Zupanc, Gunther K. H.