High-throughput RNA and Single-cell RNA Sequencing to Identify Sepsis associated Molecular Mechanisms and the Blood Immune Cell Landscape

Abstract Sepsis, a leading cause of death in intensive care units (ICUs), is a complex systemic inflammatory response to infection with high morbidity and mortality. Its pathogenesis involves dysregulated inflammation, immune dysfunction, and metabolic alterations, particularly in lactate metabolism. This study employed bioinformatics analyses to explore sepsis mechanisms and identify potential therapeutic targets. We analyzed two GEO datasets and found the lactate metabolism pathway significantly enriched in sepsis patients. Seventeen key genes were identified and used to classify sepsis into two subtypes via WGCNA and consensus clustering. These subtypes exhibited distinct clinical and immune profiles. Seven hub genes (BPI, HGF, HP, LCN2, LTF, MMP8, RETN) showed differential expression between subtypes and may serve as diagnostic biomarkers. MMP8 was identified as a critical regulator in lactate metabolism, with associated miRNAs and transcription factors predicted. Single-cell analysis revealed altered immune cell compositions and interactions in sepsis patients. Our findings offer novel insights into sepsis pathogenesis and potential therapeutic strategies targeting lactate metabolism and immune regulation.