Figure 1. IKK2ca expression in IECs induces NF-κB activation and mild intestinal inflammation.

(A) Immunoblot reveals increased IKK2 expression and reduced levels of IκBα in SI IECs from IKK2ca^IEChom mice compared with IKK2ca^sFL littermates. (B) Immunofluorescent staining with anti-FLAG antibodies shows IEC-specific expression of FLAG-IKK2ca in IKK2ca^IEChom colon sections. Background staining in the lumen of the IKK2ca^sFL colon results from incomplete removal of luminal contents. (C) EMSA reveals increased NF-κB DNA-binding activity in nuclear extracts from IKK2ca^IEChom SI and colonic IECs. (D) Representative endoscopic images of colons from 8-week-old IKK2ca^sFL and IKK2ca^IEChom mice. (E) Quantification of MEICS showing no significant colonic inflammation in 7- to 9-week-old IKK2ca^IEChom (n = 10) mice compared with IKK2ca^sFL (n = 5) littermates. Data are presented as mean ± SD. (F) H&E-stained sections show crypt elongation and increased immune cell infiltration in the SI and colon of IKK2ca^IEChom compared with IKK2ca^sFL mice. Note the lack of Paneth cells in ileal crypts in IKK2ca^IEChom mice (indicated by white arrows in inset). The black arrow indicates a mislocalized Paneth cell. Scale bars: 50 μm.