Table6_Identification of key pathways, genes and immune cell infiltration in hypoxia of high-altitude acclimatization via meta-analysis and integrated bioinformatics analysis.XLSX

Background: For individuals acutely exposed to high-altitude regions, environmental hypobaric hypoxia induces several physiological or pathological responses, especially immune dysfunction. Therefore, hypoxia is a potentially life-threatening factor, which has closely related to high-altitude acclimatization. However, its specific molecular mechanism is still unclear.
Methods: The four expression profiles about hypoxia and high altitude were downloaded from the Gene Expression Omnibus database in this study. Meta-analysis of GEO datasets was performed by NetworkAnalyst online tool. Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene ontology (GO) enrichment analysis, and visualization were performed using R (version 4.1.3) software, respectively. The CIBERSORT analysis was conducted on GSE46480 to examine immune cell infiltration. In addition, we experimentally verified the bioinformatics analysis with qRT-PCR.
Results: The meta-analysis identified 358 differentially expressed genes (DEGs), with 209 upregulated and 149 downregulated. DEGs were mostly enriched in biological processes and pathways associated with hypoxia acclimatization at high altitudes, according to both GO and KEGG enrichment analyses. ERH, VBP1, BINP3L, TOMM5, PSMA4, and POLR2K were identified by taking intersections of the DEGs between meta-analysis and GSE46480 and verified by qRT-PCR experiments, which were inextricably linked to hypoxia. Immune infiltration analysis showed significant differences in immune cells between samples at sea level and high altitudes.
Conclusion: Identifying the DEGs and pathways will improve our understanding of immune function during high-altitude hypoxia at a molecular level. Targeting hypoxia-sensitive pathways in immune cells is interesting in treating high-altitude sickness. This study provides support for further research on high-altitude acclimatization.

研究背景：对于急性暴露于高海拔地区的个体而言，环境低压低氧会诱发多种生理或病理反应，尤以免疫功能紊乱最为显著。低氧是一类潜在的致命性影响因素，与高原习服（high-altitude acclimatization）密切相关，但其具体的分子机制仍未明确。
研究方法：本研究从基因表达综合数据库（Gene Expression Omnibus, GEO）中下载了4组与低氧及高海拔相关的表达谱数据集。借助NetworkAnalyst在线工具完成GEO数据集的荟萃分析；分别使用R软件（版本4.1.3）开展京都基因与基因组百科全书（Kyoto Encyclopedia of Genes and Genomes, KEGG）富集分析、基因本体论（Gene Ontology, GO）富集分析及可视化操作。针对GSE46480数据集进行CIBERSORT分析，以检测免疫细胞浸润情况。此外，本研究通过实时定量聚合酶链反应（quantitative real-time polymerase chain reaction, qRT-PCR）对生物信息学分析结果进行实验验证。
研究结果：荟萃分析共筛选出358个差异表达基因（differentially expressed genes, DEGs），其中209个上调、149个下调。GO与KEGG富集分析结果均显示，差异表达基因主要富集于与高原低氧习服相关的生物学过程及通路中。通过取荟萃分析与GSE46480数据集的差异表达基因交集，筛选得到ERH、VBP1、BINP3L、TOMM5、PSMA4及POLR2K这6个基因，经qRT-PCR实验验证，它们与低氧过程密切相关。免疫细胞浸润分析显示，海平面与高海拔样本的免疫细胞组成存在显著差异。
研究结论：本研究筛选得到的差异表达基因及相关通路，可提升我们在分子层面对高原低氧环境下免疫功能的认知。靶向免疫细胞内低氧敏感通路有望为高原病的治疗提供新思路，本研究也为后续高原习服相关研究提供了理论支撑。