Department of Molecular, Cell and Cancer Biology
Amino Acids, Peptides, and Proteins | Cell Biology | Cellular and Molecular Physiology | Digestive System Diseases | Enzymes and Coenzymes | Gastroenterology | Hepatology | Molecular Biology
BACKGROUND AND AIMS: Tumor necrosis factor (TNF) is a major pathogenic effector and a therapeutic target in inflammatory bowel disease (IBD), yet the basis for TNF-induced intestinal epithelial cell (IEC) death is unknown, because TNF does not kill normal IECs. Here, we investigated how chronic nuclear factor (NF)- kappaB activation, which occurs in human IBD, promotes TNF-dependent IEC death in mice.
METHODS: Human IBD specimens were stained for p65 and cleaved caspase-3. C57BL/6 mice with constitutively active IKKbeta in IEC (Ikkbeta(EE)(IEC)), Ripk1(D138N/D138N) knockin mice, and Ripk3(-/-) mice were injected with TNF or lipopolysaccharide. Enteroids were also isolated from these mice and challenged with TNF with or without RIPK1 and RIPK3 inhibitors or butylated hydroxyanisole. Ripoptosome-mediated caspase-8 activation was assessed by immunoprecipitation.
RESULTS: NF-kappaB activation in human IBD correlated with appearance of cleaved caspase-3. Congruently, unlike normal mouse IECs that are TNF-resistant, IECs in Ikkbeta(EE)(IEC) mice and enteroids were susceptible to TNF-dependent apoptosis, which depended on the protein kinase function of RIPK1. Constitutively active IKKbeta facilitated ripoptosome formation, a RIPK1 signaling complex that mediates caspase-8 activation by TNF. Butylated hydroxyanisole treatment and RIPK1 inhibitors attenuated TNF-induced and ripoptosome-mediated caspase-8 activation and IEC death in vitro and in vivo.
CONCLUSIONS: Contrary to common expectations, chronic NF-kappaB activation induced intestinal crypt apoptosis after TNF stimulation, resulting in severe mucosal erosion. RIPK1 kinase inhibitors selectively inhibited TNF destructive properties while preserving its survival and proliferative properties, which do not require RIPK1 kinase activity. RIPK1 kinase inhibition could be a potential treatment for IBD.
Cell Death, IBD, Intestinal Epithelial Cell, RIPK1, Ripoptosome
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© 2019 The Authors. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
DOI of Published Version
Cell Mol Gastroenterol Hepatol. 2019 Oct 10. pii: S2352-345X(19)30138-9. doi: 10.1016/j.jcmgh.2019.10.002. [Epub ahead of print] Link to article on publisher's site
Cellular and molecular gastroenterology and hepatology
Wong J, Zelic M, Bertin J, Kelliher MA, Guma M. (2019). RIPK1 Mediates TNF-Induced Intestinal Crypt Apoptosis During Chronic NF-kappaB Activation. Open Access Articles. https://doi.org/10.1016/j.jcmgh.2019.10.002. Retrieved from https://escholarship.umassmed.edu/oapubs/4006
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
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