Sepsis transcriptomics and validation identify PFKFB2 as a regulator of early inflammation and later lactate-dependent M2-like programming in LPS-stimulated macrophages

Sepsis involves dynamic immune dysfunction and metabolic reprogramming, but the role of lactylation-associated metabolic genes in macrophage responses remains unclear. We integrated four peripheral-blood transcriptomic datasets using differential expression analysis, weighted gene co-expression network analysis, and four machine-learning algorithms. Thirty candidate genes were identified, and a 12-gene signature was obtained; PFKFB2 was selected for functional validation based on its consistent upregulation across sepsis cohorts and previous evidence linking PFKFB2-mediated glycolytic regulation to lactate production and macrophage functional adaptation. In LPS-stimulated THP-1-derived macrophages, PFKFB2 silencing reduced extracellular lactate at 6 and 24 h. At 6 h, silencing attenuated TNF and IL1B induction, and sodium L-lactate did not restore this response. At 24 h, silencing increased TNF and IL1B while decreasing MRC1 and IL10 ; these changes were partially reversed by sodium L-lactate. Thus, PFKFB2 supports early pro-inflammatory gene induction and later sustains a lactate-dependent M2-like transcriptional program. These findings connect multi-cohort sepsis transcriptomics with functional evidence and identify PFKFB2 as a metabolic regulator of macrophage inflammatory transitions.