Lungs were preserved in RNAlater and frozen in -80ºC. Samples were homogenized in TRIzol reagent, extracted with chloroform and further cleaned using E.Z.N.A Total RNA kit I (Omega Bio-tek). Total RNA was treated with Dnase I. Illumina-compatible library construction was performed by the QB3 Vincent J. Coates Genomics Sequencing Laboratory at the University of California, Berkeley. PolyA selection was performed. Standard size libraries were constructed using Kapa Biosystems library preparation kits.