Fu Xiujuan, He Yizi, Xie Yongzhi, Lu Zuneng
Department of Neurology, Renmin Hospital of Wuhan University, Wuhan, China.
Department of Lymphoma and Hematology, Hunan Cancer Hospital, The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Changsha, China.
Front Neurosci. 2023 Mar 2;17:1113216. doi: 10.3389/fnins.2023.1113216. eCollection 2023.
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by progressive and selective degeneration of motor neurons in the motor cortex of brain and spinal cord. Ferroptosis is a newly discovered form of cell death and reported to mediate selective motor neuron death in the mouse model of ALS. The growing awareness of ferroptosis and iron metabolism dysfunction in ALS prompted us to investigate the expression pattern of ferroptosis and iron metabolism-related genes (FIRGs) in ALS. Here, we performed a conjoint analysis of bulk-RNA sequence and single-nucleus RNA sequence data using the datasets from Gene Expression Omnibus (GEO) to reveal the role of FIRGs in ALS, especially in selective motor neuron death of ALS. We first investigated the differentially expressed genes (DEGs) between ALS and non-neurological controls. Weighted gene co-expression network analysis constructed the gene co-expression network and identified three modules closely associated with ALS. Fifteen FIRGs was identified as target genes based on least absolute shrinkage and selection operator regression analysis as follows: ACSL4, ANO6, ATP6V0E1, B2M, CD44, CHMP5, CYBB, CYBRD1, HIF1A, MOSPD1, NCF2, SDCBP, STEAP2, TMEM14C, ULK1. These genes could differentiate ALS patients from non-neurological controls ( < 2.2e-16) and had a valid value in predicting and diagnosing ALS (AUC = 0.881 in primary dataset and AUC = 0.768 in validation dataset). Then we performed the functional enrichment analysis of DEGs between ALS cases, the most significantly influenced by target genes, and non-neurological controls. The result indicated that the most significantly influenced functions in ALS pathogenesis by these identified FIRGs are synapse pathways, calcium signaling pathway, cAMP signaling pathway, and phagosome and several immune pathways. At last, the analysis of single- nuclear seq found that CHMP5, one of the 15 FIRGs identified by bulk single-nucleus RNA-seq data, was expressed significantly higher in ALS than pathologically normal (PN), specifically in excitatory neuron populations with layer 2 and layer 3 markers (Ex L2_L3), layer 3 and layer 5 markers (Ex L3_L5). Taken together, our study indicates the positive correlation between FIRGs and ALS, presents potential markers for ALS diagnosis and provides new research directions of CHMP5 function in selective motor neuron death in ALS.
肌萎缩侧索硬化症（ALS）是一种神经退行性疾病，其特征是大脑和脊髓运动皮层中的运动神经元进行性和选择性退化。铁死亡是一种新发现的细胞死亡形式，据报道在ALS小鼠模型中介导选择性运动神经元死亡。对ALS中铁死亡和铁代谢功能障碍的认识不断提高，促使我们研究ALS中铁死亡和铁代谢相关基因（FIRGs）的表达模式。在这里，我们使用来自基因表达综合数据库（GEO）的数据集对批量RNA序列和单核RNA序列数据进行联合分析，以揭示FIRGs在ALS中的作用，特别是在ALS选择性运动神经元死亡中的作用。我们首先研究了ALS与非神经学对照之间的差异表达基因（DEGs）。加权基因共表达网络分析构建了基因共表达网络，并确定了与ALS密切相关的三个模块。基于最小绝对收缩和选择算子回归分析，确定了15个FIRGs作为靶基因，如下所示：ACSL4、ANO6、ATP6V0E1、B2M、CD44、CHMP5、CYBB、CYBRD1、HIF1A、MOSPD1、NCF2、SDCBP、STEAP2、TMEM14C、ULK1。这些基因可以将ALS患者与非神经学对照区分开来（<2.2e-16），并且在预测和诊断ALS方面具有有效价值（在原始数据集中AUC = 0.881，在验证数据集中AUC = 0.768）。然后，我们对受靶基因影响最显著的ALS病例与非神经学对照之间的DEGs进行了功能富集分析。结果表明，这些确定的FIRGs在ALS发病机制中影响最显著的功能是突触途径、钙信号通路、cAMP信号通路、吞噬体和一些免疫途径。最后，单核序列分析发现，批量单核RNA-seq数据确定的15个FIRGs之一CHMP5在ALS中的表达明显高于病理正常（PN），特别是在具有第2层和第3层标记（Ex L2_L3）、第3层和第5层标记（Ex L3_L5）的兴奋性神经元群体中。综上所述，我们的研究表明FIRGs与ALS之间存在正相关，为ALS诊断提供了潜在标志物，并为CHMP5在ALS选择性运动神经元死亡中的功能提供了新的研究方向。
