TGFB1 and idiopathic pulmonary fibrosis: In 2004, Watts et al. found that simvastatin, which blocks Rho prenylation and its subsequent signaling, can significantly inhibit CTGF gene expression in normal human lung fibroblasts (IMR 90 cells) and IPF-derived lung fibroblasts (LL29, LL97a, and HIPF cells), modulate TGF-β/CTGF interactions, and specifically override the potent induction of CTGF by TGF-β [87].