Conversely, the preconditioning of anti-TGF-β antibody can inhibit the expression of S1PL mRNA and protein induced by TGF-β in human lung fibroblasts, which indicates that, in pulmonary fibrosis, the role of S1P and its signaling pathways also depends on the level of TGF-β (Huang and Natarajan, 2015). This evidence concerns the gene TGFB1 and pulmonary fibrosis.