Multifaceted Immunomodulatory Nanocomplexes Target Neutrophilic-ROS Inflammation in Acute Lung Injury

The sepsis-induced acute lung injury (ALI) still represents one of the leading causes of death in critically ill patients, underscoring the need for novel therapies. Excessive activation of immune cells and damage of reactive oxygen species (ROS) are the main factors that exacerbate lung injury. Here, the multifaceted immunomodulatory nanocomplexes targeting the proinflammatory neutrophilic activation and ROS damage are established. The S100A8/9 inhibitor, ABR2575, is loaded in the nanocomplexes, which effectively blocks the neutrophils-S100A8/A9- toll-like receptors (TLRS)-Inflammasome signaling in ALI. Synergically, the SiH nanosheets are encapsulated together with ABR2575 into the core of poly(lactic-co-glycolic acid) (PLGA) nanosponges, to achieve sustainable hydrogen release for the alleviation of ROS-induced lung tissue injury, and also promote the M2 polarization of macrophages. This novel combination strategy is proven to significantly suppress the infiltration of neutrophils and pro-inflammatory macrophages into the lungs, decrease the activation of neutrophils and pro-inflammatory monocytes in the blood, facilitate the anti-inflammatory polarization of macrophages and monocytes, and reduce the expression of pro-inflammatory cytokines in both the lung and blood circulation, all of which alleviate the lung injuries in preclinical murine ALI models. The current investigations offer a novel nanomedicine for the treatment of ALI with great potential in clinical invention.