AFM41a: A Novel PAD2 Inhibitor for Sepsis Treatment-Efficacy and Mechanism.

Pseudomonas aeruginosa (PA) infection can cause pneumonia and sepsis by activating peptidyl-arginine deiminase (PAD) and triggering the formation of neutrophil extracellular traps (NETs). Our previous research has elucidated the crucial role of PAD2 in regulating CitH3 production and NETosis signaling following bacterial infection. Therefore, targeting PAD2 with selective inhibitors holds promise for treating PA-induced sepsis. Here, we compare the structure and function of two PAD2 inhibitors, AFM32a and AFM41a, and investigate their biological effects in mice subjected with PA. We analyze their impact on PAD2 inhibition, macrophage polarization, and other host defense mechanisms against PA-induced sepsis utilizing both in vivo and in vitro approaches. Our findings demonstrate that both PAD2 inhibitors (AFM32a and AFM41a) and Pad2 deficiency substantially enhance protection against PA-induced sepsis, with AFM41a showing superior efficacy over AFM32a. This protective effect is marked by improved survival rates, reduced bacterial growth in mice subjected to PA infection, and the promotion of M2 macrophage polarization coupled with enhanced autophagic activity. Our results advocate for targeting PAD2 as an effective strategy to bolster host defenses against PA infection. Utilizing AFM41a to promote M2 macrophage polarization and autophagy offers promising avenues for the treatment of PA infection and the improvement of sepsis outcomes.