Wang Zhili, He Yu, Cun Yupeng, Li Qinyuan, Zhao Yan, Luo Zhengxiu
National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Department of Respiratory Medicine, Children's Hospital of Chongqing Medical University, Chongqing, China.
China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing Key Laboratory of Translational Medical Research in Cognitive Development and Learning and Memory Disorders, Children's Hospital of Chongqing Medical University, Chongqing, China.
Front Cell Dev Biol. 2023 Apr 13;11:1164544. doi: 10.3389/fcell.2023.1164544. eCollection 2023.
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. 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. 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. Overall, these findings reveal the potential role of the iron metabolism-related gene SLC40A1 in the pathogenesis of childhood allergic asthma.
哮喘是儿童中最常见的慢性疾病，其中过敏性哮喘是最常见的表型，约占病例的80%。越来越多的证据表明，铁稳态和铁调节分子的破坏可能与儿童过敏性哮喘有关。然而，其潜在的分子机制仍不清楚。分析了三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。确定了三个数据集中常见的铁代谢相关差异表达基因（DEG），并对其进行功能富集分析。研究了关键铁代谢相关DEG与2型气道炎症基因之间可能的相关性。单细胞转录组分析进一步确定了驱动关键基因表达的主要气道细胞亚群。通过定量逆转录聚合酶链反应（qRT-PCR）和免疫荧光，在儿童哮喘患者和对照个体的支气管肺泡灌洗（BAL）细胞中验证了关键铁代谢相关基因SLC40A1。通过Perls铁染色评估BAL细胞内的铁含量，并通过铁测定法测量BAL上清液中的铁水平，以评估儿童哮喘患者的气道铁代谢状态。确定了五个常见的铁代谢相关DEG，它们在功能上与铁稳态相关。在这些基因中，下调的SLC40A1与2型气道炎症标志物密切相关，SLC40A1的基因特征可能用于确定儿童过敏性哮喘患者中的2型高和2型低亚群。进一步的单细胞转录组分析确定了驱动SLC40A1表达的气道巨噬细胞。免疫荧光染色显示FPN（由SLC40A1编码）与巨噬细胞标志物CD68共定位。通过qRT-PCR和免疫荧光分析验证了SLC40A1（FPN）的下调。结果进一步表明，儿童过敏性哮喘患者的BAL液中铁水平降低，但BAL细胞中铁积累增加。此外，SLC40A1表达降低与过敏性哮喘儿童气道中铁水平降低密切相关。总体而言，这些发现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。
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