Qian et al. found that the expression level of collagen I in fibroblasts was significantly increased after co-culturing with ECs that were isolated from mouse lung tissue treated with BLM; in addition, activated ECs in BLM-treated mouse lung tissue resulted in an increased secretion of TGF-β1 and CTGF, which in turn promoted the activation, collagen synthesis, and transformation of resident fibroblasts [90]. Here, CCN2 is linked to Bloom syndrome.