Fuzheng Jiedu formula attenuates acute pneumonia by coordinated regulation of macrophage NLRP3 inflammasome and neutrophil NETs.

BACKGROUND: Fuzheng Jiedu Formula (FZJD) is a polyherbal prescription that is commonly used in the treatment of infectious diseases, particularly infectious pneumonia. However, the key molecular mechanisms underlying its empirical therapeutic effects have not yet been fully elucidated. This study aimed to assess the anti-pneumonia efficacy of FZJD and elucidate its underlying regulatory mechanisms. Furthermore, it aimed to identify the plasma-exposed phytochemicals that may contribute to these pharmacological effects. METHODS: A mouse model of Pseudomonas aeruginosa (PA-14) pneumonia was employed to evaluate the in vivo efficacy of FZJD. UPLC/Q-TOF-MS analyses were conducted to identify FZJD extracts and its plasma exposure components. Quantitative proteomics and non-targeted metabolomics combined with network pharmacology were used to map key molecular pathways. In parallel, in vitro assays conducted in macrophages and neutrophils evaluated the effects of FZJD's key active compounds on inflammation and NETs formation. RESULTS: Oral FZJD (10-40 g/kg) dose-dependently improved lung histopathology, limited macrophage and neutrophil infiltration, and lowered circulating TNF-α, IL-1β, and IL-6. Multi-omics integration analysis identified the NLRP3 signaling pathway and NETs formation as key dysregulated processes that were effectively reversed by FZJD treatment. Concordantly, lungs from treated mice showed lower p‑NF‑κB/NF‑κB, NLRP3, and cleaved caspase‑1, together with reduced cit‑H3/MPO and MPO-cfDNA complexes. Among 31 plasma-exposure constituents, saikosaponin A, prunasin, aloe-emodin, and glycyrrhizic acid emerged as multifunctional inhibitors that blocked NF-κB activation, curtailed NLRP3 assembly, and restrained NETosis in vitro. Pathway readouts supported actions on complementary axes (TLR4-IRAK1, STING1-IFN-β, FPR1-AKT, CASP8, and HDAC2-H3K9ac), providing a mechanistic basis for their collective protection against pneumonia. CONCLUSIONS: FZJD mitigates acute pneumonia by dampening macrophage NLRP3 inflammasome activation while restraining neutrophil NETosis. The mechanistic study provides evidence supporting the traditional use of FZJD in the treatment of respiratory infections and underscores its potential as a host-directed therapy.