On the other hand, KLF4, known as another master player in self-renew and differentiation of stem cells, was downregulated in IPF-MSCs; this result is in line with those by Lin [24] that reported decreased level of KLF4 in lung tissues of human IPF and mouse models of bleomycin-induced pulmonary fibrosis. Here, KLF4 is linked to idiopathic pulmonary fibrosis.