In situ neutrophil apoptosis and macrophage efferocytosis mediated by Glycyrrhiza protein nanoparticles for acute inflammation therapy.

In the progression of acute inflammation, the activation and recruitment of macrophages and neutrophils are mutually reinforcing, leading to amplified inflammatory response and severe tissue damage. Therefore, to regulate the axis of neutrophils and macrophages is essential to avoid tissue damage induced from acute inflammatory. Apoptotic neutrophils can regulate the anti-inflammatory activity of macrophages through the efferocytosis. The strategy of in situ targeting and inducing neutrophil apoptosis has the potential to modulate macrophage activity and transfer anti-inflammatory drugs. Herein, a natural glycyrrhiza protein nanoparticle loaded with dexamethasone (Dex@GNPs) was constructed, which could simultaneously regulate neutrophil and macrophage function during acute inflammation treatment by combining in situ neutrophil apoptosis and macrophage efferocytosis. Dex@GNPs can be rapidly and selectively internalized by neutrophils and subsequently induce neutrophils apoptosis through a ROS-dependent mechanism. The efferocytosis of apoptotic neutrophils not only promoted the polarization of macrophages into anti-inflammatory state, but also facilitated the transfer of Dex@GNPs to macrophages. This enabled dexamethasone to further modulate macrophage function. In mouse models of acute respiratory distress syndrome and sepsis, Dex@GNPs significantly ameliorated the disordered immune microenvironment and alleviated tissue injury. This study presents a novel strategy for drug delivery and inflammation regulation to effectively treat acute inflammatory diseases.