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Mechanisms of Transglutaminase 2 (TG2)-Mediated Gene Expression in Astrocyte

星形胶质细胞中转谷氨酰胺酶 2 (TG2) 介导的基因表达机制

基本信息

批准号：
10293984
负责人：
Gail V. W. Johnson
金额：
$ 42.35万
依托单位：
UNIVERSITY OF ROCHESTER
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-08-01 至 2024-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10293984
关键词：
ATAC-seq Affect Applications Grants Astrocytes Attenuated Awareness Binding Binding Sites Biology Calcium Calcium Binding Cell Death Cell Survival ChIP-seq Chimeric Proteins Chromatin Co-Immunoprecipitations DNA Binding Data Deletion Mutagenesis Environment Future GTP Binding Gene Expression Gene Expression Profile Gene Expression Regulation Genes Genomics Guanosine Triphosphate Guanosine Triphosphate Phosphohydrolases Health In Vitro Individual Injury Knowledge Label Link Mediating Molecular Molecular Conformation Mus Neuraxis Neurons Outcome Pathway interactions Pharmaceutical Preparations Phenocopy Phenotype Play Process Proteins Reaction Recovery Regulation Resistance Role Signal Transduction Techniques Testing Wild Type Mouse base central nervous system injury decorin high resolution imaging in vivo Model inhibitor/antagonist mutant next generation novel response response to injury scaffold transamidases transcription factor transcriptome transcriptome sequencing transglutaminase 2 whole genome

项目摘要

Astrocytes play an indispensable role in maintaining a healthy environment for neuronal function, and in mediating the response of the CNS to injury. Following an injury astrocytes become “reactive” and mediate both helpful and harmful outcomes depending on their gene expression profile. However the molecular mechanisms that regulate gene expression in astrocytes and thus their response to injury has not been fully delineated. One protein that plays a key role in regulating the response of astrocytes to insults is transglutaminase 2 (TG2). Deletion or depletion of TG2 results in astrocytes taking on a more “helpful” phenotype, however the underlying molecular mechanisms are unknown. TG2 is a multifunctional protein; it catalyzes a calcium dependent transamidation reaction, binds and hydrolyzes GTP and can function as a scaffold or linker protein. TG2 undergoes large conformational changes mediated by calcium and GTP binding, and its conformation can dictate its function independent of its enzymatic activities. These conformational states are key a factors in determining cell survival/cell death outcomes. There is a growing awareness that TG2 likely regulates gene expression, however the mechanisms of TG2-mediated regulation of gene expression in astrocytes has not been fully explored. One possible mechanism may be by TG2 interacting with, and modulating the function of, a protein that plays a pivotal role in regulating gene expression. One factor that plays a key role in regulating chromatin accessibility and the activity of specific transcription factors is Zbtb7a. Intriguingly, preliminary data indicate that TG2 interacts with Zbtb7a, and binding sites for these transcription factors are in the majority of pro-survival genes that are upregulated in TG2-/- astrocytes. The UNDERLYING PREMISE of this proposal is that TG2 plays a role in regulating gene expression in astrocytes, and thus how they respond to injury. However, a CRITICAL KNOWLEDGE GAP is how TG2 regulates gene expression. The OVERALL HYPOTHESIS of this application is that TG2, in a conformational dependent manner, moderates chromatin accessibility and the gene expression landscape, which contributes to how astrocytes respond to injury. The NOVELTY of this project is that we will be using an integrated “omic” approach (ATAC-seq, RNA-seq, ChIP-seq) and both in vitro and in vivo models of TG2+/+ and TG2-/- astrocytes to establish the mechanisms by which TG2 in a specific conformation regulates gene expression. The specific aims of this proposal are to test the hypothesis that: (1) the conformation of TG2 play an essential role in determining its ability to regulate chromatin accessibility and gene expression, and (2) TG2 mediates gene expression in astrocytes in part by regulating the function of Zbtb7a. The data generated from these novel and exploratory studies will provide the basis for a future R01 grant application focused on delineating the molecular mechanisms and pathways regulated by TG2 in astrocytes to direct outcomes following CNS injury.

星形胶质细胞在维持神经元功能的健康环境中发挥着不可或缺的作用，介导CNS对损伤的反应。损伤后，星形胶质细胞变得“反应性”并介导有益和有害的结果取决于他们的基因表达谱。然而，分子机制调节星形胶质细胞中基因表达并因此它们对损伤的反应还没有被完全描述。一在调节星形胶质细胞对损伤的反应中起关键作用的蛋白质是转氨酶2（TG 2）。 TG 2的缺失或消耗导致星形胶质细胞呈现更“有用”的表型，然而，分子机制尚不清楚。TG 2是一种多功能蛋白质;它催化钙依赖性通过转酰胺基反应，结合并水解GTP，并可作为支架或接头蛋白发挥作用。TG2 通过钙和GTP结合介导发生巨大的构象变化，并且其构象可以决定其功能独立于其酶活性。这些构象状态是决定细胞存活/细胞死亡结果。越来越多的人意识到TG 2可能调节基因表达，然而，TG 2介导的星形胶质细胞基因表达调控机制尚未完全阐明，探讨了一种可能的机制是TG 2与蛋白质相互作用并调节蛋白质的功能在调节基因表达中起着关键作用。在调节染色质中起关键作用的一个因子可及性和活性的特异性转录因子是Zbtb 7a。有趣的是，初步数据显示， TG 2与Zbtb 7a相互作用，并且这些转录因子的结合位点大多数是促存活的。在TG 2-/-星形胶质细胞中上调的基因。该提案的基本前提是，TG 2发挥在调节星形胶质细胞基因表达中的作用，从而调节它们对损伤的反应。然而，一个关键了解GAP是TG 2如何调节基因表达。本申请的总体假设 TG 2以构象依赖的方式调节染色质可及性和基因表达景观，这有助于星形胶质细胞如何应对损伤。这个项目的新奇之处在于，我们将使用整合的“组学”方法（ATAC-seq，RNA-seq，ChIP-seq）以及体外和体内模型， TG 2 +/+和TG 2-/-星形胶质细胞，以建立特定构象的TG 2调节基因表达。本研究的具体目的是验证以下假设：（1）TG 2的构象在决定其调节染色质可及性和基因表达的能力方面发挥重要作用，以及（2） TG 2部分通过调节Zbtb 7a的功能来介导星形胶质细胞中的基因表达。生成的数据这些新的探索性研究将为未来的R 01资助申请提供基础，描绘星形胶质细胞中TG 2调节的分子机制和途径，以指导以下结果： CNS损伤。

项目成果

期刊论文数量（4）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Deletion of Transglutaminase 2 from Mouse Astrocytes Significantly Improves Their Ability to Promote Neurite Outgrowth on an Inhibitory Matrix.

DOI：
10.3390/ijms24076058
发表时间：
2023-03-23
期刊：
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
影响因子：
5.6
作者：
Emerson, Jacen;Delgado, Thomas;Girardi, Peter;Johnson, Gail V. W.
通讯作者：
Johnson, Gail V. W.

Stabilizing transglutaminase 2 in the open conformation results in reactive astrocytes being more neurosupportive.

将转谷氨酰胺酶 2 稳定在开放构象会导致反应性星形胶质细胞更具神经支持性。

DOI：
10.1101/2024.04.15.589192
发表时间：
2024
期刊：
bioRxiv : the preprint server for biology
影响因子：
0
作者：
Emerson,Jacen;Delgado,Thomas;Hong,Matthew;Keillor,JeffreyW;Johnson,GailVw
通讯作者：
Johnson,GailVw

Deletion or Inhibition of Astrocytic Transglutaminase 2 Promotes Functional Recovery after Spinal Cord Injury.

DOI：
10.3390/cells10112942
发表时间：
2021-10-29
期刊：
Cells
影响因子：
6
作者：
Elahi A;Emerson J;Rudlong J;Keillor JW;Salois G;Visca A;Girardi P;Johnson GVW;Pröschel C
通讯作者：
Pröschel C