Metabolomic profiling of host–pathogen interactions: differential effects of Gram-positive and Gram-negative bacterial secretomes on THP-1 macrophage metabolism

Infectious diseases present substantial health and economic challenges worldwide. The increasing prevalence of multidrug-resistant bacteria in both community and hospital settings has emerged as a global health issue that necessitates innovative strategies for prompt diagnosis and treatment. Metabolomics, which provides comprehensive insights into the biochemical alterations of cellular phenotypes, has emerged as a valuable approach for studying host-pathogen interactions and identifying novel therapeutic targets. In this study, untargeted liquid chromatography-mass spectrometry (LC-MS)-based metabolite profiling was employed to investigate the differential effects of the secretome from Gram-positive <i>S. aureus</i> SH1000 and Gram-negative <i>P. aeruginosa</i> PAO1 on THP-1 macrophages. The results revealed that both bacterial secretomes modulate several key metabolic pathways, including alanine, aspartate and glutamate metabolism; sphingolipid metabolism; glycine and serine metabolism; glycolipid metabolism; and tryptophan metabolism. Distinct metabolic trends were observed between the two secretomes: <i>S. aureus</i> induced an accumulation of asparagine and l-formylkynurenine, alongside depletion of glycine-related intermediates (<i>e.g.</i> sarcosine, guanidinoacetate), whereas <i>P. aeruginosa</i> altered creatine levels and reduced asparagine and l-kynurenine. Notably, shared effects were also identified, with both secretomes demonstrating similar significant effects (FDR < 0.05 and VIP > 1) on arginine and proline metabolism in THP-1 macrophages. These findings highlight both shared and unique pathogen-specific metabolic responses, offering preliminary insights into host metabolic reprogramming triggered by exemplar Gram-positive and Gram-negative bacteria. These results provide a foundation for future studies to explore bacterial pathogenesis and to identify therapeutic strategies against resistant infections.