Background

A better understanding of the mechanism(s) underlying cardioembolic stroke can promote recovery and reduce the risk of recurrent embolisms.

Methods

Peripheral blood mononuclear cell (PBMC) gene expression datasets from cardioembolic patients and healthy controls were obtained from the Gene Expression Omnibus (GEO) database (GSE58294). The Limma software package was utilized to identify differentially-expressed genes (DEGs). Protein-protein interaction (PPI) analysis of the DEGs was performed using STRING. A weighted gene co-expression network analysis (WGCNA) was used to build a gene co-expression network. In vitro experiments assessed the effects on neutrophils exposed to oxygen and glucose-deprived (OGD) cortical neurons. An in vivo murine model of thromboembolic stroke was constructed through thrombin injection to examine effects on circulating neutrophils. Mechanistic in vitro studies were conducted using the proteasome inhibitor MG132, the p53-Mdm2 binding inhibitor Nutlin-3a, Mdm2 small-interfering RNA (siRNA), and Ctnnb1 siRNA.

Results

DEG analysis identified 44 upregulated and 66 downregulated genes in cardioembolic stroke PBMCs. PPI analysis of these DEGs yielded one eight-node protein module with β-catenin (CTNNB1) as the central hub protein. Integration of the DEGs with WGCNA-derived hub genes revealed the key hub DEGs CTNNB1 and mouse double minute 2 (MDM2). Follow-up experiments revealed Mdm2, p53, and phospho-β-catenin upregulation in neutrophils exposed to OGD neurons in vitro and following thromboembolic stroke in vivo. Mechanistic studies revealed that neutrophils transcriptionally upregulate Ctnnb1 expression to compensate for Mdm2/p53-mediated β-catenin degradation induced by exposure to OGD neurons, thereby promoting neutrophil survival.

Conclusion

Compensatory Ctnnb1 transcriptional upregulation in neutrophils induced by ischemic neuron exposure may be involved in promoting neutrophil survival following cardioembolic stroke.

中文翻译：

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Ctnnb1转录上调补偿了心肌栓塞性中风后中性粒细胞中Mdm2 / p53介导的β-catenin降解。

背景

更好地了解心脏栓塞性中风的机制可以促进恢复并降低再次发生栓塞的风险。

方法

来自心脏栓塞患者和健康对照者的外周血单核细胞（PBMC）基因表达数据集可从基因表达综合（GEO）数据库（GSE58294）获得。Limma软件包用于鉴定差异表达基因（DEG）。使用STRING对DEG进行蛋白质-蛋白质相互作用（PPI）分析。加权基因共表达网络分析（WGCNA）用于构建基因共表达网络。体外实验评估了暴露于缺氧和缺糖（OGD）皮质神经元的嗜中性粒细胞的影响。通过凝血酶注射建立体内血栓栓塞性中风的鼠模型，以检查其对循环中性粒细胞的影响。使用蛋白酶体抑制剂MG132，p53-Mdm2结合抑制剂Nutlin-3a，

结果

DEG分析确定了心脏栓塞性中风PBMC中的44个上调基因和66个下调基因。这些DEG的PPI分析产生了一个八节点蛋白模块，其中β-catenin（CTNNB1）为中心枢纽蛋白。DEGs与WGCNA衍生的中枢基因的整合揭示了关键的中枢DEG CTNNB1和小鼠双分钟2（MDM2）。后续实验显示，在体外和体内血栓栓塞性中风后，暴露于OGD神经元的中性粒细胞的Mdm2，p53和磷酸化β-catenin上调。机理研究表明，嗜中性粒细胞转录上调Ctnnb1表达，以补偿暴露于OGD神经元引起的Mdm2 / p53介导的β-连环蛋白降解，从而促进嗜中性粒细胞的存活。

结论

缺血性神经元暴露诱导的中性粒细胞中的补偿性Ctnnb1转录上调可能参与促进心脏栓塞性中风后中性粒细胞的存活。