library_construction_protocol: U937 cells Total RNA was purified from 1 million cells using Rneasy plus isolation kit (QIAGEN) following the manufacturer instructions and 1uL of a 1:10 diltion of ERCC Spike-in mix (Thermo Fisher) was added to each sample. U937 RNA-Seq libraries were prepared with the TruSeq mRNA kit from Illunima according to the standard protocol.