HIF1A and pulmonary fibrosis: To further improve inhalation treatment of idiopathic pulmonary fibrosis (IPF) by liposomal PGE2, siRNAs targeted to major proteins responsible for the lung damage under IPF (MMP3, CCL12, and HIF1A) were added to the NLC based nanoparticles containing PGE2 and tested on the similar experimental model of lung fibrosis using inhalation delivery.[23] This enhanced advance system was more effective in the treatment of IPF when compared with siRNA and PGE2 delivered separately.