Repression of TSC1/TSC2 mediated by MeCP2 regulates human embryo lung fibroblast cell differentiation and proliferation.

Pulmonary fibrosis (PF) is a severe inflammatory disease with limited effective treatments. It is known that the transdifferentiation of human embryo lung fibroblast (HELF) cells from pulmonary fibroblasts into myofibroblasts, contributes to the progression of pulmonary fibrogenesis. The tuberous sclerosis proteins TSC1 and TSC2 are two key signaling factors which can suppress cell growth and proliferation. However, the roles of TSC1 and TSC2 in lung fibroblast are unclear. Here, we developed a PF model with bleomycin (BLM) in mice and conducted several simulation experiments in HELF cells. Our study shows that the expression of TSC1 and TSC2 in fibrotic mice lung was reduced and stimulation of HELF cells with TGF-β1 resulted in a down-regulation of TSC1 and TSC2. In addition, overexpression of TSC1 or TSC2 decreased cell proliferation and differentiation. Furthermore, we found that reduced expression of TSC1 and TSC2 caused by TGF-β1 is associated with the promoter methylation status of TSC1 and TSC2. MeCP2, controls an epigenetic pathway that promotes myofibroblast transdifferentiation and fibrosis. We found that expression of TSC1 and TSC2 can be repressed by MeCP2, which regulates HELF cell differentiation and proliferation as myofibroblasts and lead to PF ultimately.