Control of extracellular matrix remodeling by CD29+ astrocytes

项目摘要/摘要 细胞外基质(ECM)重塑是中枢神经系统(CNS) 奖赏底物，如伏隔核(NAC)，能适应环境中不可预测的应激源。 细胞外基质是一种空间、分子和细胞上的异质性结构，它影响神经活动、细胞-细胞。 相互作用和血脑屏障的完整性。然而，暴露在反复的不可预测的压力下会导致 ECM的分子和细胞重组，影响电路水平对应力引导的适应 神经活动和行为。细胞外基质重塑部分由整合素控制：跨膜受体 通过将ECM相关多肽锚定到多种细胞类型来调节ECM。重要的是，ECM包括 神经元突起和星形胶质细胞的终足，星形胶质细胞是中枢神经驻留的神经胶质细胞。星形胶质细胞使 通过表达多种积极参与ECM重塑的整合素，联系整个ECM。 通过细胞外基质中的这些亲密相互作用，星形胶质细胞准备好控制神经活动和行为。 然而，星形胶质细胞形成NAC ECM的机制和细胞-细胞相互作用 不可预测的压力在很大程度上是未知的。在之前的研究中，我把重点放在 中枢神经系统星形胶质细胞亚群对炎症的反应。我鉴定了b1整合素CD29是 中枢神经系统内星形胶质细胞表达的顶级标志物。CD29参与与其他细胞的多个复合体 影响ECM组织的整合素。我之前的数据表明CD29+星形胶质细胞可能由 通过与不同的细胞相互作用，在细胞外基质重塑中起互补作用的不同亚群 类型。然而，在体内快速研究星形胶质细胞亚群之间的相互作用一直是一个历史性的挑战。 为此，我最近开发了一种名为RABID-SEQ的新技术，它描述了星形胶质细胞与其他细胞之间的相互作用 高通量、全基因组规模和单细胞转录精确度的细胞。因此，狂犬病- SEQ是确定细胞外基质中CD29+星形胶质细胞亚群相互作用的候选工具 不可预知的压力。在这项提案中，我正在寻求一个新的研究方向，以确定 暴露在不可预测的压力下会影响CD29+星形胶质细胞的相互作用、定位和功能。我假设 定义的CD29+星形胶质细胞亚群调节不同的ECM结构域，这些结构域影响对 不可预知的压力。我建议从以下几个具体目标来检验这一假设。在目标1中，我将定义 急慢性反应NAC内表达整合素的CD29+星形胶质细胞亚群的相互作用 使用raid-seq和cite-seq的不可预测压力。在目标2中，我将对占据的ECM域进行空间映射 通过CD29+NAC星形胶质细胞各亚群的空间转录和CD29+CKO小鼠来揭示CD29+是如何 星形胶质细胞重塑ECM以应对压力。在目标3中，我将定义CD29+NAC星形胶质细胞如何调节 小白蛋白+中间神经元在暴露于不可预测的压力后的奖赏寻求范式中的活动。 综上所述，我将研究应激如何影响NAC CD29+星形胶质细胞的相互作用、位置和功能。

PROJECT SUMMARY/ABSTRACT Remodeling of the extracellular matrix (ECM) is a central mechanism by which central nervous system (CNS) reward substrates, such as the nucleus accumbens (NAc), adapt to unpredictable stressors in the environment. The ECM is a spatially, molecularly, and cellularly heterogeneous structure that impacts neural activity, cell-cell interactions, and blood-brain barrier integrity. However, exposure to repeated unpredictable stress leads to molecular and cellular reorganization of the ECM, which influences circuit-level adaptations to stress guiding neural activity and behavior. ECM remodeling is partially controlled by integrins: transmembrane receptors that regulate the ECM by anchoring ECM-associated peptides to multiple cell types. Cellularly, the ECM consists of neuronal processes and also the endfeet of astrocytes, which are CNS-resident glial cells. Astrocytes make contacts throughout the ECM by expressing multiple integrins that actively participate in ECM remodeling. Through these intimate interactions within the ECM, astrocytes are poised to control neural activity and behavior. However, the mechanisms and cell-cell interactions by which astrocytes shape the NAc ECM in response to unpredictable stress are largely unknown. In PREVIOUS RESEARCH EFFORTS I focused on characterizing the responses of astrocyte subsets in the CNS in response to inflammation. I identified the b1 integrin CD29 as a top marker expressed by astrocytes throughout the CNS. CD29 participates in multiple complexes with other integrins that affect ECM organization. My previous data suggest that CD29+ astrocytes might be composed of heterogeneous subsets that play complementary roles in remodeling the ECM by interacting with distinct cell types. However, it has been historically challenging to rapidly study the interactions of astrocyte subsets in vivo. To this end, I recently developed a new technique called RABID-seq that profiles astrocyte interactions with other cells at high throughput, on the genome-wide scale, and with single-cell transcriptomic precision. Thus, RABID- seq is a candidate tool to define the interactions of CD29+ astrocyte subsets in the ECM in response to unpredictable stress. In this proposal, I AM PURSUING A NEW RESEARCH DIRECTION to identify how exposure to unpredictable stress shapes CD29+ astrocyte interactions, localization, and function. I hypothesize that defined subsets of CD29+ astrocytes regulate distinct ECM domains that influence behavioral responses to unpredictable stress. I propose to test this hypothesis in the following Specific Aims. In Aim 1, I will define the interactions of integrin-expressing CD29+ astrocyte subsets within the NAc in response to acute and chronic unpredictable stress using RABID-seq and CITE-seq. In Aim 2, I will spatially map the ECM domains occupied by each subset of CD29+ NAc astrocytes via spatial transcriptomics and CD29 cKO mice to uncover how CD29+ astrocytes remodel the ECM in response to stress. In Aim 3, I will define how CD29+ NAc astrocytes regulate the activity of parvalbumin+ interneurons in a reward-seeking paradigm after exposure to unpredictable stress. IN SUMMARY, I will study how stress affects the interactions, location, and function of NAc CD29+ astrocytes.