TIMP1 and pulmonary fibrosis: Coincidently, two NF-κB-regulated genes encoding pro-fibrotic mediators, TIMP1 and OPN, are evidently induced in fibroblasts and myofibroblasts in MWCNT-exposed lungs, which confirms the transactivation of NF-κB and indicates the pro-fibrotic function of NF-κB in MWCNT-induced lung fibrosis.