Multi-omics study to elucidate molecular mechanism of polyhexamethylene guanidine phosphate (PHMG-p)-induced pulmonary damage in mice

Polyhexamethylene guanidine phosphate (PHMG-p), a cationic disinfectant previously used in humidifiers, has been linked to severe pulmonary diseases in Korea. This study aimed to elucidate the molecular mechanisms underlying PHMG-p–induced lung toxicity using an integrated multi-omics approach. BALB/c mice were intratracheally instilled with PHMG-p (0, 0.03, 0.1 mg/kg, twice weekly for 4 weeks). Histopathology revealed dose-dependent pulmonary lesions, including inflammatory infiltration, alveolar wall hyperplasia, and fibrosis. Transcriptomic profiling identified 213 and 1,506 differentially expressed genes (DEGs) in the low- and high-dose groups, respectively, with enriched pathways related to immune activation, cytokine signaling, and cellular stress responses. Proteomic analysis detected 148 and 1,168 differentially expressed proteins (DEPs), many of which overlapped with DEGs and were associated with chemokine signaling, protein refolding, and ion transport dysregulation. Metabolomic profiling of serum samples identified dose-responsive alterations in amino acid and energy metabolism, with notable increases in glutamate, leucine, serine, and related metabolites. Integrated omics analysis revealed consistent up-regulation of CDKN1A, HSP90AA1, HSPA1A, HSPA8, and HSPH1, and down-regulation of FPR1, suggesting their roles as potential biomarkers of PHMG-p–induced pulmonary injury. Pathway convergence indicated activation of inflammatory and fibrotic remodeling processes, as well as metabolic reprogramming involving glutamate and branched-chain amino acid pathways. These findings provide mechanistic insight into PHMG-p–induced lung toxicity and highlight multi-omics signatures that may serve as biomarkers for monitoring or predicting pulmonary damage caused by cationic polymer biocides.