Alternatively, because Nrp2 is highly expressed on smooth muscle cells (SMCs) of the colon, and conditional knockout of Nrp2 in SMCs (Nrp2fl/flSM22a-CreERT2) leads to increased contractility [79], Nrp2 may play a role in SMC contractility during asthma attacks. This evidence concerns the gene NRP2 and asthma.