PCSK6	Proprotein convertase subtilisin/kexin type 6
IPF	Idiopathic pulmonary fibrosis
PAR-1	Protease-activated receptor-1
ECM	Excessive extracellular matrix
ERK	Extracellular signal-regulated kinase
α-SMA	α-smooth muscle actin
PACE4	Paired basic amino-acid-cleaving enzyme 4
SPC4	Subtilisin-like proprotein convertase 4
MMPs	Matrix metalloproteinases
TGF-β	Transforming growth factor-β
IGF-2	Insulin-like Growth Factor 2
HNE	4-hydroxy-2-nonenal
NHLF	Normal human lung fibroblast
FACS	Flow cytometry
CM	Conditioned medium
SEM	Standard error of the mean