Sofalcone

Sofalcone, a gastroprotective drug, covalently binds to KEAP1 to activate Nrf2 resulting in anti-colitic activity

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.

[Sofalcone]

Sofalcone upregulates the nuclear factor (erythroid-derived 2)-like 2/heme oxygenase-1 pathway, reduces soluble fms-like tyrosine kinase-1, and quenches endothelial dysfunction: potential therapeutic for preeclampsia

Preeclampsia is a severe complication of pregnancy, characterized by hypertension, oxidative stress, and severe endothelial dysfunction. Antiangiogenic factors, soluble fms-like tyrosine kinase-1 (sFlt-1) and soluble endoglin, play key pathophysiological roles in preeclampsia. Heme oxygenase-1 (HO-1) is a cytoprotective, antioxidant enzyme reported to be downregulated in preeclampsia. Studies propose that inducing HO-1 may also decrease sFlt-1 production. Sofalcone, a gastric antiulcer agent in clinical use, is known to induce HO-1 in gastric epithelium. We aimed to investigate whether sofalcone induces HO-1 and reduces sFlt-1 release from primary human placental and endothelial cells and blocks endothelial dysfunction in vitro. We isolated human trophoblasts and endothelial cells (human umbilical vein endothelial cells) and also used uterine microvascular cells. We investigated the effects of sofalcone on (1) HO-1 production, (2) activation of the nuclear factor (erythroid-derived 2)-like 2 pathway, (3) sFlt-1 and soluble endoglin release, (4) tumor necrosis factor α-induced monocyte adhesion and vascular cell adhesion molecule upregulation, and (5) endothelial tubule formation. Sofalcone potently increased HO-1 mRNA and protein in both primary trophoblasts and human umbilical vein endothelial cells. Furthermore, sofalcone treatment caused nuclear translocation of nuclear factor (erythroid-derived 2)-like 2 and transactivation of other nuclear factor (erythroid-derived 2)-like 2 responsive genes (NQO1, TXN, and GCLC). Importantly, sofalcone significantly decreased the secretion of sFlt-1 from primary human trophoblasts. Sofalcone potently suppressed endothelial dysfunction in 2 in vitro models, blocking tumor necrosis factor α-induced monocyte adhesion and vascular cell adhesion molecule 1 expression in human umbilical vein endothelial cells. These results indicate that in primary human tissues, sofalcone can potently activate antioxidant nuclear factor (erythroid-derived 2)-like 2/HO-1 pathway, decrease sFlt-1 production, and ameliorate endothelial dysfunction. We propose that sofalcone is a novel therapeutic candidate for preeclampsia.

Sofalcone, a gastric mucosa protective agent, increases vascular endothelial growth factor via the Nrf2-heme-oxygenase-1 dependent pathway in gastric epithelial cells

Sofalcone, 2'-carboxymethoxy-4,4-bis(3-methyl-2-butenyloxy)chalcone, is an anti-ulcer agent that is classified as a gastric mucosa protective agent. Recent studies indicate heat shock proteins such as HSP32, also known as heme-oxygenase-1(HO-1), play important roles in protecting gastrointestinal tissues from several stresses. We have previously reported that sofalcone increases the expression of HO-1 in adipocytes and pre-adipocytes, although the effect of sofalcone on HO-1 induction in gastrointestinal tissues is not clear. In the current study, we investigated the effects of sofalcone on the expression of HO-1 and its functional role in rat gastric epithelial (RGM-1) cells. We found that sofalcone increased HO-1 expression in RGM-1 cells in both time- and concentration-dependent manners. The HO-1 induction was associated with the nuclear translocation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) in RGM-1 cells. We also observed that sofalcone increased vascular endothelial growth factor (VEGF) production in the culture medium. Treatment of RGM-1 cells with an HO-1 inhibitor (tin-protoporphyrin), or HO-1 siRNA inhibited sofalcone-induced VEGF production, suggesting that the effect of sofalcone on VEGF expression is mediated by the HO-1 pathway. These results suggest that the gastroprotective effects of sofalcone are partly exerted via Nrf2-HO-1 activation followed by VEGF production.

Sofalcone, an anti-ulcer chalcone derivative, suppresses inflammatory crosstalk between macrophages and adipocytes and adipocyte differentiation: implication of heme-oxygenase-1 induction

Sofalcone, 2'-carboxymethoxy-4,4'-bis(3-methyl-2-butenyloxy)chalcone, has been used as an anti-ulcer agent, although its precise molecular mechanism has not been completely understood. In the current study, we tested the effects of sofalcone on the inflammatory crosstalk between macrophages and adipocytes and on the differentiation of pre-adipocytes. We found that sofalcone has a strong suppressive effect on the production of nitric oxide (NO), tumor necrosis factor (TNF)alpha, and monocyte chemoattractant protein (MCP)-1 in the culture medium of a coculture system containing RAW264.7 macrophages and 3T3-F442A adipocytes stimulated with lipopolysaccharide (LPS). The suppressive effect of sofalcone on NO production was attenuated by treatment with tin-protoporphyrin (SnPP), a heme-oxygenase (HO)-1 inhibitor. Western blotting analysis showed that sofalcone increased HO-1 expression in both 3T3-F442A mature adipocytes and undifferentiated fibroblasts. Sofalcone also inhibited the differentiation of 3T3-F442A pre-adipocytes into adipocytes, which was restored by SnPP treatment. These results suggest that sofalcone has preferable properties for obesity or metabolic syndrome.