Table2_Transcriptomic analysis identified SLC40A1 as a key iron metabolism-related gene in airway macrophages in childhood allergic asthma.CSV

Introduction: Asthma is the most common chronic condition in children, with allergic asthma being the most common phenotype, accounting for approximately 80% of cases. Growing evidence suggests that disruption of iron homeostasis and iron regulatory molecules may be associated with childhood allergic asthma. However, the underlying molecular mechanism remains unclear.
Methods: Three childhood asthma gene expression datasets were analyzed to detect aberrant expression profiles of iron metabolism-related genes in the airways of children with allergic asthma. Common iron metabolism-related differentially expressed genes (DEGs) across the three datasets were identified and were subjected to functional enrichment analysis. Possible correlations between key iron metabolism-related DEGs and type 2 airway inflammatory genes were investigated. Single-cell transcriptome analysis further identified major airway cell subpopulations driving key gene expression. Key iron metabolism-related gene SLC40A1 was validated in bronchoalveolar lavage (BAL) cells from childhood asthmatics with control individuals by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and immunofluorescence. The intracellular iron content in BAL cells was assessed by Perls iron staining and the iron levels in BAL supernatant was measured by iron assay to assess airway iron metabolism status in childhood asthmatics.
Results: Five common iron metabolism-related DEGs were identified, which were functionally related to iron homeostasis. Among these genes, downregulated SLC40A1 was strongly correlated with type 2 airway inflammatory markers and the gene signature of SLC40A1 could potentially be used to determine type 2-high and type 2-low subsets in childhood allergic asthmatics. Further single-cell transcriptomic analysis identified airway macrophages driving SLC40A1 expression. Immunofluorescence staining revealed colocalization of FPN (encoded by SLC40A1) and macrophage marker CD68. Down-regulation of SLC40A1 (FPN) was validated by qRT-PCR and immunofluorescence analysis. Results further indicated reduced iron levels in the BAL fluid, but increased iron accumulation in BAL cells in childhood allergic asthma patients. Furthermore, decreased expression of SLC40A1 was closely correlated with reduced iron levels in the airways of children with allergic asthma.
Discussion: Overall, these findings reveal the potential role of the iron metabolism-related gene SLC40A1 in the pathogenesis of childhood allergic asthma.

Introduction: 哮喘是儿童最常见的慢性疾病，其中过敏性哮喘是最常见的表型（phenotype），约占所有病例的80%。越来越多的证据表明，铁稳态（iron homeostasis）紊乱及铁调节分子可能与儿童过敏性哮喘相关，但其潜在分子机制仍不明确。
Methods: 本研究分析了3个儿童哮喘基因表达数据集，以检测过敏性哮喘儿童气道中铁代谢相关基因的异常表达谱。本研究鉴定了3个数据集共有的铁代谢相关差异表达基因（differentially expressed genes, DEGs），并对其进行功能富集分析；同时探究了关键铁代谢相关DEGs与2型气道炎症基因间的潜在关联。单细胞转录组（single-cell transcriptome）分析进一步明确了驱动关键基因表达的主要气道细胞亚群。本研究通过定量反转录聚合酶链反应（quantitative reverse transcription-polymerase chain reaction, qRT-PCR）和免疫荧光技术，在儿童哮喘患者与对照个体的支气管肺泡灌洗液（bronchoalveolar lavage, BAL）细胞中验证了关键铁代谢相关基因SLC40A1的表达水平；同时采用普鲁士蓝铁染色（Perls iron staining）检测BAL细胞内铁含量，通过铁检测试剂盒测定BAL上清液铁水平，以评估儿童哮喘患者的气道铁代谢状态。
Results: 本研究共鉴定出5个共有的铁代谢相关DEGs，其功能与铁稳态相关。在这些基因中，表达下调的SLC40A1与2型气道炎症标志物显著相关；SLC40A1的基因特征或可用于区分儿童过敏性哮喘患者的2型高表达与2型低表达亚群。进一步的单细胞转录组分析明确了驱动SLC40A1表达的气道巨噬细胞亚群。免疫荧光染色显示，膜铁转运蛋白（ferroportin, FPN，由SLC40A1编码）与巨噬细胞标志物CD68存在共定位。qRT-PCR与免疫荧光分析均验证了SLC40A1（FPN）的表达下调。研究结果进一步显示，儿童过敏性哮喘患者的BAL液中铁水平降低，但BAL细胞内铁蓄积增加。此外，SLC40A1的表达下调与儿童过敏性哮喘患者气道内铁水平降低显著相关。
Discussion: 综上，本研究结果揭示了铁代谢相关基因SLC40A1在儿童过敏性哮喘发病机制中的潜在作用。