Stabilizing transglutaminase 2 in the open conformation results in reactive astrocytes being more neurosupportive.
Stabilizing transglutaminase 2 in the open conformation results in reactive astrocytes being more neurosupportive.
复制标题
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
复制
发表时间：
2024
期刊：
影响因子：
--
通讯作者：
Johnson,GailVw
中科院分区：
文献类型：
--
作者：
Emerson,Jacen;Delgado,Thomas;Hong,Matthew;Keillor,JeffreyW;Johnson,GailVw
星形胶质细胞在维持中枢神经系统（CNS）的结构和代谢平衡中起着关键作用。中枢神经系统损伤导致星形胶质细胞的一系列反应性表型的发展，其分子决定因素知之甚少。找到调节星形胶质细胞损伤反应和利用促恢复表型的方法在治疗CNS损伤方面具有希望。最近，已经证明，星形胶质细胞转氨酶2（TG 2）的消融使反应性星形胶质细胞向改善体外和体内神经元损伤结果的表型转变。此外，在体内小鼠模型中，用不可逆抑制剂VA 4药理学抑制TG 2表型模拟了星形胶质细胞中TG 2缺失的神经支持作用。在这项研究中，我们扩展了VA 4治疗和TG 2缺失的比较，以深入了解TG 2在损伤后减弱神经支持性星形胶质细胞功能的机制。使用神经元-星形胶质细胞共培养模型，我们发现VA 4处理提高了星形胶质细胞在损伤相关基质上支持神经突生长的能力，正如我们先前对星形胶质细胞TG 2缺失所显示的那样。我们假设TG 2通过转录调控介导其对星形胶质细胞表型的影响，我们以前的RNA测序表明，TG 2主要是在星形胶质细胞中的转录抑制，尽管它可以促进基因表达的上调和下调。因此，我们询问VA 4抑制是否可以改变TG 2与Zbtb 7a的相互作用，Zbtb 7a是一种转录因子，我们以前确定为功能相关的TG 2核相互作用因子。我们发现VA 4显著降低了TG 2和Zbtb 7a的相互作用。此外，我们评估了TG 2缺失和VA 4处理对转录允许的组蛋白乙酰化的影响，发现两个实验组中的乙酰化显著更高。与这些发现相一致，我们目前的蛋白质组学分析进一步支持TG 2在星形胶质细胞中的主要转录抑制作用。我们的蛋白质组学数据还揭示了TG 2缺失或抑制的星形胶质细胞中脂质和抗氧化剂代谢的显著变化，这可能有助于增强这些星形胶质细胞的神经支持功能。
Astrocytes play critical roles in supporting structural and metabolic homeostasis in the central nervous system (CNS). CNS injury leads to the development of a range of reactive phenotypes in astrocytes whose molecular determinants are poorly understood. Finding ways to modulate astrocytic injury responses and leverage a pro-recovery phenotype holds promise in treating CNS injury. Recently, it has been demonstrated that ablation of astrocytic transglutaminase 2 (TG2) shifts reactive astrocytes towards a phenotype that improves neuronal injury outcomes both in vitro and in vivo. Additionally, in an in vivo mouse model, pharmacological inhibition of TG2 with the irreversible inhibitor VA4 phenocopied the neurosupportive effects of TG2 deletion in astrocytes. In this study, we extended our comparisons of VA4 treatment and TG2 deletion to provide insights into the mechanisms by which TG2 attenuates neurosupportive astrocytic function after injury. Using a neuron–astrocyte co-culture model, we found that VA4 treatment improves the ability of astrocytes to support neurite outgrowth on an injury-relevant matrix, as we previously showed for astrocytic TG2 deletion. We hypothesize that TG2 mediates its influence on astrocytic phenotype through transcriptional regulation, and our previous RNA sequencing suggests that TG2 is primarily transcriptionally repressive in astrocytes, although it can facilitate both up- and downregulation of gene expression. Therefore, we asked whether VA4 inhibition could alter TG2’s interaction with Zbtb7a, a transcription factor that we previously identified as a functionally relevant TG2 nuclear interactor. We found that VA4 significantly decreased the interaction of TG2 and Zbtb7a. Additionally, we assessed the effect of TG2 deletion and VA4 treatment on transcriptionally permissive histone acetylation and found significantly greater acetylation in both experimental groups. Consistent with these findings, our present proteomic analysis further supports the predominant transcriptionally repressive role of TG2 in astrocytes. Our proteomic data additionally unveiled pronounced changes in lipid and antioxidant metabolism in astrocytes with TG2 deletion or inhibition, which likely contribute to the enhanced neurosupportive function of these astrocytes.