Unraveling the developmental role of Cajal-Retzius neurons during the establishment of neocortical circuits in mice

揭示 Cajal-Retzius 神经元在小鼠新皮质回路建立过程中的发育作用

• 批准号: 442680687
• 负责人: Dr. Oriane Blanquie, Ph.D.
• 金额: --
• 依托单位: Institut für Physiologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/442680687?language=en
• 关键词: Unraveling; developmental; role; Cajal; Retzius

Cajal-Retzius neurons (CRNs) represent a transient population of neurons necessary for the laminar organization of the neocortex. CRNs populate the outer layer of the neocortex before being eliminated by apoptosis by the end of the second post-natal week. CRNs seem well integrated into the neocortex: they display complex and long-range axonal processes, receive GABAergic-mediated inputs and are able to fire action potentials. I have recently demonstrated that excitatory GABAA-receptor mediated inputs are necessary to trigger their cell death. However, whether CRNs participate into the typical in vivo activity patterns displayed by developing cortical networks and whether this activity is necessary for the establishment of sensory cortical circuits has not yet been investigated. Here, I will investigate whether CRNs display spontaneous and sensory-evoked activity in vivo, and whether their electrical activity then translates into a developmental function. Experiments will be performed in the barrel field of the primary somatosensory cortex (S1BF), a region that displays a topographic map of the whisker pad.If CRNs participate in the establishment of the topographic representation of somatosensory stimuli, I expect them to be responsive to sensory inputs. In the first part of the funding, the identity of presynaptic neurons sending inputs into S1BF CRNs will be established by combining monosynaptic retrograde viral tracing, clearing and immunostaining procedures on transgenic mice.In a second part of the project, I plan to investigate whether CRNs participate into the spontaneous, synchronous activity in vivo and assess the role of whisker stimulation in their electrical activity. To this aim, mouse pups will be injected in the outer layer of the somatosensory cortex with a calcium indicator. In vivo calcium imaging will then be performed with and without mechanical whisker stimulation.In the last part of the project, the effect of CRNs silencing on the developing network will be assessed. CRNs will be specifically silenced in newborn mice using Designer Receptors Exclusively Activated by Designer Drugs (DREADDs), and the effect of silencing CRNs on the activity patterns of S1BF neurons and S1BF architecture will be assessed.To conclude, the experiments described in this funding proposal will allow the description of the spontaneous- and sensory-evoked activity patterns of S1BF CRNs in vivo as well as their anatomical inputs. These experiments will further unravel a putative causal relationship between the activity of CRNs and establishment of functional cortical circuits.

Cajal-Retzius神经元(CRN)是新皮质板层组织所必需的一组瞬时神经元。CRN分布在新皮质的外层，在出生后第二周结束时被细胞凋亡消除。CRN似乎很好地整合到新皮质：它们显示复杂和长距离的轴突，接受GABA能介导的输入，并能够发射动作电位。我最近证明，兴奋性GABAA受体介导的输入是触发细胞死亡所必需的。然而，CRN是否参与了大脑皮层网络发育所表现出的典型的体内活动模式，以及这种活动是否对建立感觉大脑皮层回路是必要的，还没有得到研究。在这里，我将调查CRN是否在体内表现出自发的和感觉诱发的活动，以及它们的电活动是否随后转化为发育功能。实验将在初级躯体感觉皮质(S1BF)的桶状区域进行，该区域显示胡须垫的地形图。如果CRN参与体感刺激的地形图表征，我预计它们将对感觉输入做出反应。在资金的第一部分，通过结合单突触逆行病毒追踪、清除和转基因小鼠的免疫染色程序，将建立向S1BF CRN发送信息的突触前神经元的身份。在项目的第二部分，我计划调查CRN是否参与体内的自发、同步活动，并评估胡须刺激在其电活动中的作用。为此，小鼠幼鼠将被注射到体感皮质的外层，并带有钙指示剂。然后，在有和没有机械晶须刺激的情况下进行体内钙成像。在项目的最后部分，将评估CRN沉默对发育中的网络的影响。在新生小鼠中，CRN将被设计药物(DREADD)特异性激活的设计者受体特异性沉默，并将评估沉默CRN对S1BF神经元和S1BF结构的活动模式的影响。综上所述，这项资金提案中描述的实验将允许描述S1BF CRN在体内的自发和感觉诱发的活动模式及其解剖输入。这些实验将进一步揭开CRN活性和功能皮层回路建立之间的假定因果关系。