MAPK3 and pulmonary hypertension: MIF has been found to be related to proliferation of SMCs (Calandra et al., 1994; Chen et al., 2004; Onodera et al., 2004), and a study on rats under hypobaric hypoxia showed that an increase in MIF induces proliferation of PASMCs through activation of ERK1/2 and JNK proteins, contributing to the pulmonary hypertension (Zhang et al., 2012).