ACTA1 and idiopathic pulmonary fibrosis: Figure 5 (A–B) shows that levels of α-SMA were not modified in control fibroblasts while significantly decreased upon treatment in IPF cells at early passages. This finding was associated with a concomitant reduction of type-I collagen expression in IPF fibroblasts (Figure 5C). Conversely, no changes in α-SMA and collagen expression occurred in NAC-exposed IPF cells at late passages (Figure 5, panels D–E).