Colon-Targeted Delivery Facilitates the Therapeutic Switching of Sofalcone, a Gastroprotective Agent, to an Anticolitic Drug via Nrf2 Activation

Delivery of Transcriptional Factors for Activating Antioxidant Defenses against Inflammatory Bowel Disease

Oxidative stress caused by the overproduction of reactive oxygen species (ROS) plays an important role in inflammatory bowel disease (IBD). It is well-known that the Nrf2-ARE (antioxidative response element) pathway is important in the regulation mechanism of antioxidant defense. Therefore, Nrf2 activation may be an effective therapeutic strategy for IBD. Here, we reported the development of a nucleus-targeted Nrf2 delivery nanoplatform, termed N/LC, that could accumulate in inflamed colonic epithelium, reduce inflammatory responses, and restore epithelium barriers in a murine model of acute colitis. N/LC nanocomposites could quickly escape from lysosomes, so Nrf2 largely accumulated in the nucleus of colonic cells, activated the Nrf2-ARE signaling pathway, further elevated the expression levels of downstream detoxification and antioxidant genes, and protected cells from oxidative damage. These results suggested that N/LC might be a potential nanoplatform for IBD therapy. The study provided the basis for the biomedical applications of Nrf2-based therapeutics in various diseases.

N-Acetylserotonin is an oxidation-responsive activator of Nrf2 ameliorating colitis in rats

N-Acetylserotonin (NAS) is an intermediate in the melatonin biosynthetic pathway. We investigated the anti-inflammatory activity of NAS by focusing on its chemical feature oxidizable to an electrophile. NAS was readily oxidized by reaction with HOCl, an oxidant produced in the inflammatory state. HOCl-reacted NAS (Oxi-NAS), but not NAS, activated the anti-inflammatory nuclear factor erythroid 2-related factor 2 (Nrf2)-heme oxygenase (HO)-1 pathway in cells. Chromatographic and mass analyses demonstrated that Oxi-NAS was the iminoquinone form of NAS and could react with N-acetylcysteine possessing a nucleophilic thiol to form a covalent adduct. Oxi-NAS bound to Kelch-like ECH-associated protein 1, resulting in Nrf2 dissociation. Moreover, rectally administered NAS increased the levels of nuclear Nrf2 and HO-1 proteins in the inflamed colon of rats. Simultaneously, NAS was converted to Oxi-NAS in the inflamed colon. Rectal NAS mitigated colonic damage and inflammation. The anticolitic effects were significantly compromised by the coadministration of an HO-1 inhibitor.

N-benzyl-N-methyldecan-1-amine and its derivative mitigate 2,4- dinitrobenzenesulfonic acid-induced colitis and collagen-induced rheumatoid arthritis

As our previous study revealed that N-benzyl-N-methyldecan-1-amine (BMDA), a new molecule originated from Allium sativum, exhibits anti-neoplastic activities, we herein explored other functions of the compound and its derivative [decyl-(4-methoxy-benzyl)-methyl-amine; DMMA] including anti-inflammatory and anti-oxidative activities. Pretreatment of THP-1 cells with BMDA or DMMA inhibited tumor necrosis factor (TNF)-α and interleukin (IL)-1β production, and blocked c-jun terminal kinase (JNK), p38 mitogen-activated protein kinase (MAPK), MAPKAP kinase (MK)2 and NF-κΒ inflammatory signaling during LPS stimulation. Rectal treatment with BMDA or DMMA reduced the severity of colitis in 2,4-dinitrobenzenesulfonic acid (DNBS)-treated rat. Consistently, administration of the compounds decreased myeloperoxidase (MPO) activity (representing neutrophil infiltration in colonic mucosa), production of inflammatory mediators such as cytokine-induced neutrophil chemoattractant (CINC)-3 and TNF-α, and activation of JNK and p38 MAPK in the colon tissues. In addition, oral administration of these compounds ameliorated collagen-induced rheumatoid arthritis (RA) in mice. The treatment diminished the levels of inflammatory cytokine transcripts, and protected connective tissues through the expression of anti-oxidation proteins such as nuclear factor erythroid-related factor (Nrf)2 and heme oxygenase (HO)1. Additionally, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels did not differ between the BMDA- or DMMA-treated and control animals, indicating that the compounds do not possess liver toxicity. Taken together, these findings propose that BMDA and DMMA could be used as new drugs for curing inflammatory bowel disease (IBD) and RA.

A Colon-Targeted Prodrug of Riluzole Improves Therapeutic Effectiveness and Safety upon Drug Repositioning of Riluzole to an Anti-Colitic Drug

Riluzole (RLZ) is a neuroprotective drug indicated for amyotrophic lateral sclerosis. To examine the feasibility of RLZ for repositioning as an anti-inflammatory bowel disease (IBD) drug, RLZ (2, 5, and 10 mg/kg) was administered orally to rats with colitis induced by 2,4-dinitrobenzenesulfonic acid. Oral RLZ was effective against rat colitis in a dose-dependent manner, which was statistically significant at doses over 5 mg/kg. To address safety issues upon repositioning and further improve anti-colitic effectiveness, RLZ was coupled with salicylic acid (SA) via an azo-bond to yield RLZ-azo-SA (RAS) for the targeted colonic delivery of RLZ. Upon oral gavage, RAS (oral RAS) was efficiently delivered to and activated to RLZ in the large intestine, and systemic absorption of RLZ was substantially reduced. Oral RAS ameliorated colonic damage and inflammation in rat colitis and was more effective than oral RLZ and sulfasalazine, a current anti-IBD drug. Moreover, oral RAS potently inhibited glycogen synthase kinase 3β (GSK3β) in the inflamed distal colon, leading to the suppression of NFκB activity and an increase in the level of the anti-inflammatory cytokine interleukin-10. Taken together, RAS, which enables RLZ to be delivered to and inhibit GSK3β in the inflamed colon, may facilitate repositioning of RLZ as an anti-IBD drug.

Eletrophilic Chemistry of Tranilast Is Involved in Its Anti-Colitic Activity via Nrf2-HO-1 Pathway Activation

Tranilast (TRL), a synthetic derivative of a tryptophan metabolite, is an anti-allergic drug used to treat bronchial asthma. We investigated how TRL activated the nuclear factor-erythroid 2 p45-related factor 2 (Nrf2)-hemeoxygenase-1 (HO-1) pathway based on the electrophilic chemistry of the drug and whether TRL activity contributed to the treatment of rat colitis. In human colon carcinoma cells, TRL activated Nrf2, as represented by an increase in nuclear Nrf2 and induction of Nrf2-dependent luciferase and, subsequently, HO-1, a target gene product of Nrf2. TRL activation of Nrf2 and induction of HO-1 were completely prevented by chemical reduction of the electrophilic functional group (α, β-unsaturated carbonyl group) in the drug. In parallel, TRL was reactive with the nucleophilic thiol group in N-acetylcysteine, forming a covalent adduct. Moreover, TRL, but not reduced TRL, binds to Kelch-like ECH-associated protein 1 (KEAP1), releasing Nrf2. TRL administration ameliorated colonic damage and inflammation in rats with dinitrobenzene sulfonic acid-induced colitis, which was partly compromised by the chemical reduction of TRL or co-treatment with an HO-1 inhibitor. Our results suggest that TRL activated the Nrf2-HO-1 pathway via covalent binding to KEAP1, partly contributing to TRL amelioration in rat colitis.

Cerium oxide nanoparticles acts as a novel therapeutic agent for ulcerative colitis through anti-oxidative mechanism

BACKGROUND

Cerium (IV) oxide (CeO₂) exhibit anti-inflammatory activity via scavenge free radicals and decreasing the oxygen species (ROS) production. Here we aimed to exhibit the therapeutic effect of this nanoparticle in experimental colitis models.

METHODS

Cerium oxide nanoparticles (CeONPs) were synthesized via using UiO-66 as a precursor. We used dextran sodium sulfate (DSS) to induce colitis in experimental models to investigate the anti-inflammatory effect of CeONPs. Colitis models are divided into four groups to receive the treatment, including control, colitis, cerium oxide, and sulfasalazine. We evaluated the therapeutic effects of CeONPs for the increased colitis clinical symptoms and attenuated the histological damage to colon tissue in colitis.

RESULT

This nanoparticle was significantly able to reduce the clinical symptoms of colitis. Moreover, CeONPs can enhance the disease activity index such as body lose weight, diarrhea, rectal bleeding, colon length, and spleen weight. Moreover, CeONPs showed a significant reduction in the histological characteristics of the colitis models.

CONCLUSION

These results suggest that CeONPs can be considered as promising therapeutic agents in treating the ulcerative colitis.

Therapeutic effect of an anti-tuberculosis agent, isoniazid, and its nano-isoform in ulcerative colitis

BACKGROUND

Isoniazid (INH) is well known as a first-line anti-tuberculosis, while some studies demonstrate that it has anti-inflammatory activity via a different mechanism such as inhibitionthe production of IL-1, ROS, activation of PPARγ expression, inhibition of the transcriptional regulatory activity of NF-κB and AP-1. The aim of this study, investigate the anti-inflammatory effect of INH and INH combined with Sulfasalazine-loaded nanoparticles (NPs) in the ulcerative colitis mouse model.

METHODS

To investigate the anti-inflammatory effect of INH and NPs in the ulcerative colitis mice model, we evaluated the effect of INH clinical symptoms and colonic mucosal histology in colitis.

RESULT

The present study demonstrates that combination therapy of INH with sulfasalazine as well as NPs reduces the symptom of ulcerative colitis and improved disease activity index include body lose weight, diarrhea, rectal bleeding, colonic length, spleen weight, and colon histopathological score in DSS-induced colitis mice model.

CONCLUSION

Our results suggest that the nanoforms of INH with sulfasalazine enhances the therapeutic effect of the drugs in the treatment of ulcerative colitis.