HIF1A and necrotizing enterocolitis: When miRNAs such as miR-31 and miR-203 were down-regulated in NEC tissues, they could potentiate the upsurge of proinflammatory signals mediated by TLR4, key transcription factor NFκB, hypoxia/oxidative regulators HIF1A and PTGS2, inflammatory cytokines and chemokines TNF and IL8, as well as angiogenic factor HBEGF, resulting in extensive mucosal injury (Fig 3).