Fig. 4.

IPF secreted factors activate Smad3 and induce cell proliferation via IL-6 trans-signaling. Supernatants (SN) from cultured human lung fibroblasts from patients with IPF (IPF-HLF-SN) were added to lung fibroblasts from control donors without IPF (N-HLF). Effects of the IPF-HLF-SN with/ without Tocilizumab (TCZ, 10 ng/ml) on pSmad3 protein levels and GREM1 mRNA levels were tested by Western Blot a-b and qPCR c, respectively. Lung fibroblasts derived from patients with IPF (IPF-HLF) or from control donors (N-HLF) were cultured with/ without TCZ, 10 and 100 ng/ml. Cell growth was monitored at 24, 48, and 72 h. At 24 h, culture media was changed and TCZ was added. Values are means ± SE d. One-way ANOVA was used for each time point, with the main effect of IPF-HLF versus N-HLF. *p ≤ 0.05, n = 5. The effect of IPF-HLF-SN with/ without TCZ (10 ng/ml) on cell number was tested at 24 h e. The effect of IPF-HLF-SN with/ without TCZ (10 ng/ml) on mRNA levels of αSMA (ACTA2) and Collagen1a (COL1A) were tested by qPCR at 24 h (f-g). ***p < 0.001