APOA1 and inflammatory bowel disease: HNF4A target genes are down-regulated in human IBD (Arijs et al. 2009; Haberman et al. 2014) and mouse experimental colitis (Chahar et al. 2014), and the HNF4A target APOA1 has been shown to be protective against intestinal inflammation in mice (Gkouskou et al. 2016).