Triptolide clears <i>Staphylococcus aureus</i> infection by targeting XIAP to induce host apoptosis while maintaining gut microbiota homeostasis

<h4>Background</h4><i>Staphylococcus aureus</i> (SA) remains a global health threat due to its increasing drug resistance and intracellular persistence, which compromise the conventional antibiotic efficacy. Host-directed therapy (HDT) has emerged as a promising alternative by modulating host immunity. With multi-targeting and immunomodulatory properties, traditional Chinese medicine (TCM) monomers represent ideal candidates for HDT. However, their ability to promote host immunity-mediated SA clearance remains largely unexplored.<h4>Methods</h4>Forty-one TCM monomers potentially regulating host apoptosis, a core mechanism of the host innate immune defense against intracellular pathogens, were screened to identify a compound that promotes the clearance of intracellular SA and methicillin-resistant SA (MRSA). The mechanism was investigated in infected macrophages using transcriptomics, proteomics, molecular dynamics simulations, and biochemical assays. The physiological function of the TCM monomer was examined in infected mice through lung pathology and multi-omics analysis, including transcriptomics, proteomics, metagenomics, and metabolomics.<h4>Results</h4>Triptolide was identified as a potent facilitator of host immunity-mediated intracellular clearance of SA and MRSA, without exerting direct bactericidal effects. Mechanistically, triptolide directly binds to the X-linked inhibitor of apoptosis protein (XIAP), disrupting its interaction with caspases to relieve their inhibition and thereby induce apoptosis. Furthermore, in murine infection models, triptolide treatment reduced bacterial loads, alleviated inflammation, and induced macrophage apoptosis in lungs, concurrently maintaining microbiota homeostasis and improving metabolic function.<h4>Conclusion</h4>This study establishes a proof of concept for triptolide as a HDT candidate against SA and MRSA infections, which not only enhances host apoptosis-mediated pathogen clearance but also maintains host microbiota and metabolic homeostasis.