Specifically, NF-κB is activated by MWCNTs in fibroblasts and myofibroblasts in mouse lungs and promotes the expression of tissue inhibitor of metalloproteinase 1 (TIMP1) and osteopontin (OPN), which are pro-fibrotic factors in MWCNT-induced lung fibrosis. Here, TIMP1 is linked to pulmonary fibrosis.