SART1 and pulmonary fibrosis: To address the assumption that the therapeutic effects of Sart1 siRNA-loaded liposomes on pulmonary fibrosis depend on the induction of M2 macrophages, we first depleted lung macrophages by intratracheal injection of clodronate liposomes and then treated these mice with scramble siRNA-loaded liposomes or Sart1 siRNA-loaded liposomes.