One lobe of lung was immersed in 1 ml Trizol solution (Invitrogen, 15596018) in Lysing Matrix A homogenization tubes (MP Biomedicals) immediately after dissecting from euthanized mice, and total RNAs were extracted from Trizol following the standard protocol. Total RNA from mESCs were extracted using A RNeasy miniplus kit (QIAGEN, 74136) Lung total RNA quality and quantity were examined using a Bioanalyzer (Agilent 2100, RNA 6000 nano kit). Sequencing libraries were constructed using a TruSeq Stranded Total RNA Library Prep Gold kit (Illumina, 20020599).