Moreover, Smad7 induces IKK-β expression in macrophages through direct binding and transcriptional activation of the IKK-β promoter, and IKK-β increases further Smad7 level, thereby triggering a positive feedback loop, which amplifies the inflammatory activation of macrophages in NEC (MohanKumar et al., 2016). This evidence concerns the gene IKBKB and necrotizing enterocolitis.