CX3CR1 and pulmonary fibrosis: We demonstrated: 1) a process for formulating MANPs that efficiently encapsulated the antifibrotic siRNA against TGFβ1, 2) preferential targeting of MANPs into profibrotic Mo-AMs (CX3CR1+ SiglecF+ population) that supported the key role of these cells as drivers of lung fibrosis, and 3) delivery of TGFβ siRNA via MANPs to the profibrotic macrophage population in mitigating the fibrosis burden.