sofalcone and Colitis

Sofalcone is a synthetic chalcone being used as a gastric mucosa protective agent in Japan. Sofalcone contains a 1,3-diaryl-2-propen-1-one moiety, which is a common chemical scaffold in naturally occurring chalcones. The α,β-unsaturated carbonyl group (Michael reaction acceptor) has electrophilic properties. We investigated the biochemical mechanisms by which sofalcone activated the cytoprotective and anti-inflammatory nuclear factor-erythroid 2 (NF-E2) p45-related factor 2 (Nrf2)-heme oxygenase (HO)-1 pathway. Furthermore, we investigated whether the activation of this pathway was involved in sofalcone -mediated protective effects in an experimental colitis model. Sofalcone induced HO-1 protein expression, which was dependent on increased nuclear accumulation of Nrf2 in human colon carcinoma cells. In addition, Sofalcone reacted with nucleophilic thiol compounds to form Michael adducts. A reduced form of sofalcone (SFCR) in which the Michael reaction acceptor was deactivated, did not exert biological or chemical activity. Biotin-tagged sofalcone bound to Kelch-like ECH-associated protein 1 (KEAP1), a cytosolic repressor of Nrf2. This binding was prevented by pretreatment with sofalcone and a thiol compound but not with SFCR. Furthermore, sofalcone treatment induced dissociation of the Nrf2-KEAP1 complex. Rectal administration of sofalcone alleviated colon damage and inflammation and increased colon nuclear accumulation of Nrf2 and HO-1 levels in a dinitrobenzene sulfonic acid-induced rat colitis model. The protective effects of sofalcone against colon damage and inflammation were significantly inhibited by co-administration of an HO-1 inhibitor. In conclusion, sofalcone activated the Nrf2-HO-1 pathway by covalently binding to KEAP1 via Michael addition, and may confer anti-colitic effects by inducing Nrf2 activation.

Topics: Animals; Chalcones; Colitis; Gastrointestinal Tract; Kelch-Like ECH-Associated Protein 1; Male; NF-E2-Related Factor 2; Protein Binding; Rats; Rats, Sprague-Dawley

We investigated if the therapeutic switching of sofalcone (SFC), a gastroprotective agent, to an anticolitic agent is feasible using colon-targeted drug delivery. SFC can activate the anti-inflammatory nuclear factor (erythroid-derived 2)-like 2 (Nrf2)-hemeoxygenase-1 (HO-1) pathway in human colon epithelial cells and murine macrophages. For the efficient treatment of colitis, SFC was coupled with acidic amino acids to yield SFC-aspartic acid (SFC-AA) and SFC-glutamic acid, and their colon targetability and therapeutic effects were assessed as an anticolitic agent in a 2,4-dinitrobenezenesulfonic acid-induced rat colitis model. The SFC derivatives were decoupled up to 72% in the cecal contents but remained stable in the small intestinal contents. Oral gavage of SFC-AA (oral SFC-AA, equivalent to 1.67 mg/kg of SFC) delivered SFC (maximal cecal concentration: 57.36 μM) to the cecum, while no SFC was detected with oral gavage of SFC (oral SFC, 1.67 mg/kg). Moreover, oral SFC-AA (equivalent to 10 mg/kg of SFC) did not afford detectable concentration of SFC in the blood but detected up to 4.64 μM with oral SFC (10 mg/kg), indicating efficient colonic delivery and limited systemic absorption of SFC upon oral SFC-AA. Oral SFC-AA ameliorated colonic damage and inflammation in rat colitis with elevating colonic levels of HO-1 and nuclear Nrf2 protein, and the anticolitic effects of SFC-AA were significantly undermined by an HO-1 inhibitor. At an equivalent dose of SFC, oral SFC-AA but not oral SFC increased colonic HO-1 and nuclear Nrf2 levels, and oral SFC-AA was more effective than oral SFC in treating rat colitis. Moreover, oral SFC-AA was as effective against colitis as oral sulfasalazine being used for the treatment of inflammatory bowel disease. In conclusion, colon-targeted delivery of SFC facilitated the therapeutic switching of the drug to an anticolitic drug via Nrf2 activation.

Topics: Administration, Oral; Amino Acids, Acidic; Animals; Anti-Ulcer Agents; Chalcones; Colitis; Dinitrofluorobenzene; Disease Models, Animal; Drug Delivery Systems; Epithelial Cells; Gene Knockdown Techniques; HCT116 Cells; Heme Oxygenase-1; Humans; Male; Mice; NF-E2-Related Factor 2; Protective Agents; Rats; Rats, Sprague-Dawley; RAW 264.7 Cells; Signal Transduction; Sulfasalazine; Transfection; Treatment Outcome