Alveolar macrophages play a pivotal role in maintaining pulmonary homeostasis. While their primary function is the phagocytic clearance of xenobiotic substances, our recent studies have demonstrated that they also possess a mechanism for the active uptake of bacterial-derived peptides through peptide transporter 2 (PEPT2). This finding suggests that, in addition to their role in phagocytosis, alveolar macrophages may contribute to inflammatory responses through the PEPT2-dependent internalization of bacterial peptides. In this research project, we aimed to elucidate the mechanisms of inflammation triggered by the bacterial-derived peptide iE-DAP in the absence or presence of PEPT2 inhibitors. To this end, we conducted a comprehensive proteomic analysis of the rat alveolar macrophage cell line NR8383 treated with iE-DAP, employing a highly sensitive and quantitative proteomics technique, SWATH-MS.