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

TL;DR

This study uses metabolomics to compare how secretions from two types of bacteria affect the metabolism of immune cells, revealing both shared and unique effects.

Contribution

The study identifies distinct and shared metabolic impacts of Gram-positive and Gram-negative bacterial secretomes on macrophages.

Findings

Both bacterial secretomes modulate key metabolic pathways like alanine, aspartate, and glutamate metabolism.

S. aureus caused asparagine and l-formylkynurenine accumulation and glycine depletion, while P. aeruginosa altered creatine and reduced asparagine and l-kynurenine.

Both secretomes similarly affected arginine and proline metabolism in THP-1 macrophages.

Abstract

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 S. aureus SH1000 and Gram-negative P. aeruginosa 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: S. aureus induced an accumulation of asparagine and l-formylkynurenine, alongside depletion of glycine-related intermediates (e.g. sarcosine, guanidinoacetate), whereas P. aeruginosa 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.

Treating THP-1 macrophages with S. aureus or P. aeruginosa secretome showed pronounced and distinctive metabolic disturbance.

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