Frontiers in Drug Research and Development for Inflammatory Bowel Disease

Novel targets for mucosal healing in inflammatory bowel disease therapy

Inflammatory bowel disease (IBD) is a chronic condition affecting the gastrointestinal tract, primarily manifesting as ulcerative colitis (UC) or Crohn's disease (CD). Both inflammation and disruption of the intestinal epithelial barrier are key factors in IBD pathogenesis. Substantial evidence has revealed a significant association between aberrant immune responses and impairment of the intestinal epithelial barrier in IBD pathogenesis. The components of the intestinal epithelium, particularly goblet cells and Paneth cells, are crucial to gut homeostasis, as they secrete mucin, antimicrobial peptides (AMPs), and cytokines. Furthermore, impairment of epithelial integrity, which is regulated by tight junctions, is a hallmark of IBD pathology. While common treatments for IBD, such as anti-inflammatory drugs, target various signaling pathways with varying efficacies, therapeutic approaches focused on mucosal and epithelial barrier healing have been largely neglected. Moreover, high costs, side effects, and insufficient or inconsistent therapeutic outcomes remain major drawbacks of conventional anti-IBD drugs. Recent studies on epithelial barrier regeneration and permeability reduction have introduced promising therapeutic targets, including farnesoid X receptor (FXR), urokinase-type plasminogen activator (uPA)-urokinase-type plasminogen activator receptor (uPAR) interaction, fecal microbiota transplantation (FMT), and insulin receptor (INSR). Notably, the simultaneous targeting of intestinal inflammation and promotion of epithelial barrier healing shows promise for efficient IBD treatment. Future research should explore targeted therapies and combination treatments, including natural remedies, microbiota colonization, stem cell approaches, and computer-aided drug design. It is also crucial to focus on accurate prognosis and developing a thorough understanding of IBD development mechanisms.

Sinomenine hydrochloride improves DSS-induced colitis in mice through inhibition of the Notch signaling pathway

OBJECTIVE

To study the therapeutic effect of sinomenine hydrochloride (SH) on dextran sodium sulfate (DSS)-induced colitis in mice as an animal model and the changes of Notch signaling pathway in colon tissue of mice after treatment.

METHODS

Twenty-four mice were randomly divided into control group, model group, SH low-dose group (20 mg/kg) and SH high-dose group (60 mg/kg), with 6 mice in each group. Disease activity index (DAI), colonic mucosal injury index and colonic histopathological score were calculated. The expression levels of related genes, proteins in Notch signaling pathway and inflammatory factors were quantified.

RESULTS

SH can significantly reduce the symptoms of colitis mice, and can significantly reduce the DAI score (Model: 3.44 ± 0.27; SH-20: 2.50 ± 0.18; SH-60: 1.89 ± 0.17; P < 0.001) and histopathological injury degree (Model: 7.67 ± 0.52; SH-20: 5.17 ± 0.75, P < 0.01; SH-60: 3.33 ± 0.52, P < 0.001). SH can down-regulate the expression levels of Notch1, NICD1, Jagged1 and Hes1 proteins in colon tissue of colitis mice (Model: 1.92 ± 0.16, 1.83 ± 0.21, 2.23 ± 0.22, 1.91 ± 0.17; SH-20: 1.56 ± 0.12, 1.39 ± 0.13, 1.58 ± 0.12, 1.38 ± 0.11; SH-60: 1.24 ± 0.09, 1.23 ± 0.10, 1.23 ± 0.11, 1.22 ± 0.09; P < 0.01), and reduce the contents of serum pro-inflammatory cytokines TNF-α, IL-1β and IL-6 (Model: 718.53 ± 81.81, 51.62 ± 2.80, 444.07 ± 67.77; SH-20: 544.72 ± 90.03, 34.10 ± 2.90, 345.43 ± 43.40; SH-60: 434.11 ± 71.75, 29.44 ± 3.70, 236.11 ± 29.35; P < 0.001).

CONCLUSION

The therapeutic effect of SH on DSS-induced colitis in mice may be related to inhibiting the overactivation of Notch signaling pathway.

5-Methoxytryptophan Alleviates Dextran Sulfate Sodium-Induced Colitis by Inhibiting the Intestinal Epithelial Damage and Inflammatory Response

Background

Colitis is a refractory intestinal inflammatory disease significantly affecting the quality of a patient's life and increasing the risk of exacerbation. The primary factors leading to colitis encompass infections, insufficient blood flow, and the buildup of collagen as well as white blood cells. Among various available therapeutics, 5-methoxytryptophan (5-MTP) has emerged as one of the protectants by inhibiting inflammatory damage. Nonetheless, there is no report on the role of 5-MTP in the treatment of colitis.

Materials and Methods

To verify the anti-inflammatory effect of 5-MTP in vivo, we first constructed mouse model with dextran sulfate sodium-induced colitis. Furthermore, the macrophage infiltration and release of inflammatory factors through western blot (WB) and hematoxylin-eosin staining analyses were examined. Intestinal epithelial cell tight junction damage and apoptosis were investigated by WB analysis, immunofluorescence, and terminal deoxynucleotidyl transferase dUTP nick end labeling staining. Finally, we examined the generation of cellular inflammation and analyzed the influence of 5-MTP on M1 polarization at the cellular level.

Results

This study initially confirmed that 5-MTP possessed an excellent therapeutic effect on colitis. 5-MTP inhibits macrophage infiltration and the generation of inflammatory factors. In addition to its effects on immune cells, 5-MTP significantly inhibits intestinal epithelial cell tight junction damage and apoptosis in vivo. Moreover, it inhibits inflammation and M1 polarization response in vitro.

Conclusion

5-MTP counteracts excessive inflammation, thereby preventing intestinal epithelial tight junction damage. In addition, inhibition of apoptosis suggests that 5-MTP may be a potential therapeutic agent for colitis.

Hydrogen Regulates Ulcerative Colitis by Affecting the Intestinal Redox Environment

The redox balance in the intestine plays an important role in maintaining intestinal homeostasis, and it is closely related to the intestinal mucosal barrier, intestinal inflammation, and the gut microbiota. Current research on the treatment of ulcerative colitis has focused on immune disorders, excessive inflammation, and oxidative stress. However, an imbalance in intestinal redox reaction plays a particularly critical role. Hydrogen is produced by some anaerobic bacteria via hydrogenases in the intestine. Increasing evidence suggests that hydrogen, as an inert gas, is crucial for immunity, inflammation, and oxidative stress and plays a protective role in ulcerative colitis. Hydrogen maintains the redox state balance in the intestine in ulcerative colitis and reduces damage to intestinal epithelial cells by exerting its selective antioxidant ability. Hydrogen also regulates the intestinal flora, reduces the harmful effects of bacteria on the intestinal epithelial barrier, promotes the restoration of normal anaerobic bacteria in the intestines, and ultimately improves the integrity of the intestinal epithelial barrier. The present review focuses on the therapeutic mechanisms of hydrogen-targeting ulcerative colitis.

Antioxidative effect of Periplaneta americana extract on dextran sulfate sodium-induced ulcerative colitis through activation of the Nrf2 signal

CONTEXT

Periplaneta americana L. (Blattariae) is used as a treatment for ulcerative colitis (UC) in Chinese traditional medicine.

OBJECTIVE

To evaluate the antioxidative activity of P. americana whole body ethanol extract (PAE) on UC mice and whether glycine and proline could be used for quality control and identification of active PAE components.

MATERIALS AND METHODS

NCM460 cells were pre-incubated in PAE, AA-L, AA-M, and AA-H (low, high and medium doses of proline and glycine), then treated with recombinant human TNF-α. The glutathione (GSH), malondialdehyde (MDA), superoxide dismutase (SOD) and reactive oxygen (ROS) levels were determined. UC mice were fed with water containing 2.5% dextran sulfate sodium (w/v) after pre-treatment with different doses of PAE once a day for 7 days. ELISA was used to detect the concentrations of inflammation-related factors. Colon tissues of mice were used to detect the activity of myeloperoxidase (MPO), GSH, MDA, and SOD. Histological changes were observed using H&E staining. The expression of target proteins was determined by western blotting.

RESULTS

In vivo, PAE treatment reduced the DAI score more than in the model group, restoring the weight and colonic length. It also reduced the severity of colitis, and inflammatory and oxidative stress intensity. Additionally, western blotting showed that the Nrf2 pathway was activated by PAE. In vitro PAE significantly alleviated TNF-α-induced cell damage and oxidative stress, which is relevant to the activation of the Nrf2 pathway.

CONCLUSIONS

PAE may relieve oxidative stress through the Nrf2 signaling pathway, and proline and glycine may be used as active components of its antioxidative stress activity.

Alopecia Areata: Current Treatments and New Directions

Alopecia areata is an autoimmune hair loss disease that is non-scarring and is characterized by chronic inflammation at the hair follicle level. Clinically, patients' presentation varies from patchy, circumscribed scalp involvement to total body and scalp hair loss. Current management is guided by the degree of scalp and body involvement, with topical and intralesional steroid injections as primarily first-line for mild cases and broad immunosuppressants as the mainstay for more severe cases. Until recently, the limited number of blinded, randomized, placebo-controlled clinical trials for this disease had made establishing an evidence-based treatment paradigm challenging. However, growing insights into the pathogenesis of alopecia areata through blood and tissue analysis of human lesions have identified several promising targets for therapy. T-helper (Th) 1/interferon skewing has traditionally been described as the driver of disease; however, recent investigations suggest activation of additional immune mediators, including the Th2 pathway, interleukin (IL)-9, IL-23, and IL-32, as contributors to alopecia areata pathogenesis. The landscape of alopecia areata treatment has the potential to be transformed, as several novel targeted drugs are currently undergoing clinical trials. Given the recent US FDA approval of baricitinib and ritlecitinib, Janus kinase (JAK) inhibitors are a promising drug class for treating severe alopecia areata cases. This article will review the efficacy, safety, and tolerability of current treatments for alopecia areata, and will provide an overview of the emerging therapies that are leading the revolution in the management of this challenging disease.

Modulating sphingosine 1-phosphate receptor signaling skews intrahepatic leukocytes and attenuates murine nonalcoholic steatohepatitis

Sphingosine 1-phosphate (S1P) is a bioactive sphingolipid associated with nonalcoholic steatohepatitis (NASH). Immune cell-driven inflammation is a key determinant of NASH progression. Macrophages, monocytes, NK cells, T cells, NKT cells, and B cells variably express S1P receptors from a repertoire of 5 receptors termed S1P1 - S1P5. We have previously demonstrated that non-specific S1P receptor antagonism ameliorates NASH and attenuates hepatic macrophage accumulation. However, the effect of S1P receptor antagonism on additional immune cell populations in NASH remains unknown. We hypothesized that S1P receptor specific modulation may ameliorate NASH by altering leukocyte recruitment. A murine NASH model was established by dietary feeding of C57BL/6 male mice with a diet high in fructose, saturated fat, and cholesterol (FFC) for 24 weeks. In the last 4 weeks of dietary feeding, the mice received the S1P1,4,5 modulator Etrasimod or the S1P1 modulator Amiselimod, daily by oral gavage. Liver injury and inflammation were determined by histological and gene expression analyses. Intrahepatic leukocyte populations were analyzed by flow cytometry, immunohistochemistry, and mRNA expression. Alanine aminotransferase, a sensitive circulating marker for liver injury, was reduced in response to Etrasimod and Amiselimod treatment. Liver histology showed a reduction in inflammatory foci in Etrasimod-treated mice. Etrasimod treatment substantially altered the intrahepatic leukocyte populations through a reduction in the frequency of T cells, B cells, and NKT cells and a proportional increase in CD11b+ myeloid cells, polymorphonuclear cells, and double negative T cells in FFC-fed and control standard chow diet (CD)-fed mice. In contrast, FFC-fed Amiselimod-treated mice showed no changes in the frequencies of intrahepatic leukocytes. Consistent with the improvement in liver injury and inflammation, hepatic macrophage accumulation and the gene expression of proinflammatory markers such as Lgals3 and Mcp-1 were decreased in Etrasimod-treated FFC-fed mice. Etrasimod treated mouse livers demonstrated an increase in non-inflammatory (Marco) and lipid associated (Trem2) macrophage markers. Thus, S1P1,4,5 modulation by Etrasimod is more effective than S1P1 antagonism by Amiselimod, at the dose tested, in ameliorating NASH, likely due to the alteration of leukocyte trafficking and recruitment. Etrasimod treatment results in a substantial attenuation of liver injury and inflammation in murine NASH.

Modern drug discovery for inflammatory bowel disease: The role of computational methods

Inflammatory bowel diseases (IBDs) comprising ulcerative colitis, Crohn’s disease and microscopic colitis are characterized by chronic inflammation of the gastrointestinal tract. IBD has spread around the world and is becoming more prevalent at an alarming rate in developing countries whose societies have become more westernized. Cell therapy, intestinal microecology, apheresis therapy, exosome therapy and small molecules are emerging therapeutic options for IBD. Currently, it is thought that low-molecular-mass substances with good oral bio-availability and the ability to permeate the cell membrane to regulate the action of elements of the inflammatory signaling pathway are effective therapeutic options for the treatment of IBD. Several small molecule inhibitors are being developed as a promising alternative for IBD therapy. The use of highly efficient and time-saving techniques, such as computational methods, is still a viable option for the development of these small molecule drugs. The computer-aided (in silico) discovery approach is one drug development technique that has mostly proven efficacy. Computational approaches when combined with traditional drug development methodology dramatically boost the likelihood of drug discovery in a sustainable and cost-effective manner. This review focuses on the modern drug discovery approaches for the design of novel IBD drugs with an emphasis on the role of computational methods. Some computational approaches to IBD genomic studies, target identification, and virtual screening for the discovery of new drugs and in the repurposing of existing drugs are discussed.

Sanhuang Xiexin decoction ameliorates DSS-induced colitis in mice by regulating intestinal inflammation, intestinal barrier, and intestinal flora

ETHNOPHARMACOLOGICAL RELEVANCE

Sanhuang Xiexin decoction (SXD) is a widely applicated traditional Chinese medicine (TCM) with a significant intestinal anti-inflammatory effect.

AIM OF THE STUDY

To evaluate the therapeutic effect and elucidate the possible underlying mechanisms of SXD on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) in mice.

METHODS

To model UC, 3% DSS was added to the drinking water for 7 days. The UC mice were grouped and treated with three doses of SXD (1.3, 2.6, and 6 g/kg) orally for 7 days. Mice body weight and disease activity index (DAI) scores were recorded daily. After treatment with SXD, the colon was removed, and the colon length and histopathological changes were recorded. Blood cells were counted and colonic inflammatory cytokines and oxidative stress indicators were examined. The key proteins in TLR4-MyD88-NF-κB signaling and the colonic barrier were determined by Western blot analysis. The restorative effect of SXD on intestinal flora was determined.

RESULTS

Treatment with SXD reduced DAI scores, increased body weight, improved colon shortening, and decreased colonic damage. SXD decreased the numbers of white blood cells (WBCs), increased the numbers of red blood cells (RBCs), and inhibited the expression of inflammatory cytokines and oxidative stress indicators. In addition, SXD displayed an effective anti-inflammatory effect by inhibiting the expression levels of p-IκBα, TLR4, MyD88, and p65. Furthermore, SXD significantly restored the integrity of the colonic barrier and the abundance of beneficial flora.

CONCLUSIONS

SXD significantly reduced DSS-induced colon damage when the dose was higher than 1.3 g/kg, and the middle dose group (2.6 g/kg) indicated the best effect. SXD effectively ameliorated DSS-induced UC in mice, possibly by inhibiting oxidative stress, protecting the mucosal barrier, inhibiting the TLR4-MyD88-NF-κB signaling pathway, and regulating the intestinal flora.

Anti-inflammatory and anti-oxidant properties of Melianodiol on DSS-induced ulcerative colitis in mice

Background

Ulcerative colitis is a unique inflammatory bowel disease with ulcerative lesions of the colonic mucosa. Melianodiol (MN), a triterpenoid, isolated from the fruits of the Chinese medicinal plant Melia azedarach, possesses significant anti-inflammatory properties.

Objective

The present study investigated the protective effects of MN on lipopolysaccharide (LPS)-induced macrophages and DSS-mediated ulcerative colitis in mice.

Methods

In the study, mice were given MN (50, 100, and 200 mg/kg) and 5-ASA (500 mg/kg) daily for 9 days after induction by DSS for 1 week. The progress of the disease was monitored daily by observation of changes in clinical signs and body weight.

Results

The results showed that MN effectively improved the overproduction of inflammatory factors (IL-6, NO, and TNF-α) and suppressed the activation of the NF-κB signalling cascade in LPS-mediated RAW264.7 cells. For DSS-mediated colitis in mice, MN can reduce weight loss and the disease activity index (DAI) score in UC mice, suppress colon shortening, and alleviate pathological colon injury. Moreover, MN treatment notably up regulated the levels of IL-10 and down regulated those of IL-1β and TNF-α, and inhibited the protein expression of p-JAK2, p-STAT3, iNOS, NF-κB P65, p-P65, p-IKKα/β, and p-IκBα in the colon. After MN treatment, the levels of MDA and NO in colonic tissue were remarkably decreased, whereas the levels of GSH, SOD, Nrf-2, Keap-1, HO-1, IκBα, and eNOS protein expression levels were significantly increased.

Conclusion

These results indicate that MN can activate the Nrf-2 signalling pathway and inhibit the JAK/STAT, iNOS/eNOS, and NF-κB signalling cascades, enhance intestinal barrier function, and effectively reduce the LPS-mediated inflammatory response in mouse macrophages and DSS-induced intestinal injury in UC.

Rutin-Loaded Stimuli-Responsive Hydrogel for Anti-Inflammation

An active flavonoid compound rutin was incorporated into a guanosine phenylborate hydrogel (GBR) by a stimuli-responsive borate ester linkage for the treatment of inflammatory bowel disease (IBD). The components and morphology of the drug delivery system were characterized by NMR, UV-vis spectroscopy, and AFM. Rheological measurements revealed the required injectability and self-healing ability, which contributed to its application in rectal administration. The cell assays proved the excellent compatibility and safety of the system, and a possible pathway to form multicellular aggregates. In vitro drug-release studies showed that the hydrogel exhibited good stability in physiological medium, and the drug was almost completely released (more than 90 wt % after 24 h of incubation) in acidic pH and excessive ROS-containing medium, realizing the dual-responsive release of pH/ROS. In vivo activities of the GBR hydrogel showed higher therapeutic efficacy than free rutin in a colitis mice model, and it could significantly inhibit overexpressed inflammatory cytokines, including TNF-α and IL-6. Degradation studies of the hydrogel provided further evidence for the safety of its in vivo application. The work provided a simple strategy to prepare a G-quadruplex drug carrier, which was expected to achieve multi-drug delivery.

An overview of ozanimod as a therapeutic option for adults with moderate-to-severe active ulcerative colitis

INTRODUCTION

Ulcerative colitis (UC) is a chronic inflammatory condition of the gastrointestinal tract involving a dysregulated immune response. Sphingosine-1-phosphate (S1P) is involved in immune cell regulation. S1P-receptor modulators, such as ozanimod, inhibit lymphocyte migration and have therapeutic potential in UC.

AREAS COVERED

Ozanimod is the first S1P-receptor modulator approved for the treatment of UC. It acts as a functional antagonist, causing internalization of S1P receptors on T-cells. Lymphocyte egress from lymph nodes is inhibited, and migration to sites of active inflammation is curtailed. There are several S1P-receptor subtypes, present in various organs, which inform understanding of ozanimod's side-effect profile including bradycardia and macular edema. In this review, the authors discuss the mechanism of action, pharmacokinetics, clinical efficacy, and safety profile of ozanimod in the treatment of patients with moderate-to-severe UC.

EXPERT OPINION

The S1P-receptor modulator ozanimod is an oral small molecule with a rapid onset of action and a novel therapeutic mechanism in the treatment of UC. It is an effective treatment both in bio-naïve and bio-exposed patients. Although the safety profile of ozanimod looks favorable, more long-term data are needed. Further studies are required to compare ozanimod to currently available therapies to best define its positioning in UC treatment algorithms.

Alpinia hainanensis Rhizome Extract Ameliorates Dextran Sulfate Sodium-Induced Ulcerative Colitis: Active Ingredient Investigation and Evaluation

Alpinia hainanensis is an important food spice and ethnic medicine in Southwest China. In this study, we found that the EtOAc-soluble fraction (AHE) of the A. hainanensis rhizome ethanol extract could ameliorate dextran sulfate sodium-induced ulcerative colitis (UC). To explore active constituents, five pairs of previously unreported enantiomers (1-5), together with nine known ones (6-14), were obtained. Structural characterization was achieved by comprehensive spectroscopic methods. Compounds 1 and 2 were new curcumin-butyrovanillone hybrids featuring a rare structural fragment of 2,3-dihyrofuran. The anti-inflammatory activities of isolates were evaluated, and the results indicated that compounds (-)-1, (-)-3, 6, 9, 11, and 12 significantly inhibited the nuclear factor-κB signaling pathway. These findings indicate the major active fraction of the A. hainanensis rhizome ethanol extract enriched with diarylheptanoids, flavonoids, phenolics, and their hybrid mixtures, which could be developed as a nutritional and dietary supplement for treating UC.

Target-Based Small Molecule Drug Discovery Towards Novel Therapeutics for Inflammatory Bowel Diseases

Inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), is a class of severe and chronic diseases of the gastrointestinal (GI) tract with recurrent symptoms and significant morbidity. Long-term persistence of chronic inflammation in IBD is a major contributing factor to neoplastic transformation and the development of colitis-associated colorectal cancer. Conversely, persistence of transmural inflammation in CD is associated with formation of fibrosing strictures, resulting in substantial morbidity. The recent introduction of biological response modifiers as IBD therapies, such as antibodies neutralizing tumor necrosis factor (TNF)-α, have replaced nonselective anti-inflammatory corticosteroids in disease management. However, a large proportion (~40%) of patients with the treatment of anti-TNF-α antibodies are discontinued or withdrawn from therapy because of (1) primary nonresponse, (2) secondary loss of response, (3) opportunistic infection, or (4) onset of cancer. Therefore, the development of novel and effective therapeutics targeting specific signaling pathways in the pathogenesis of IBD is urgently needed. In this comprehensive review, we summarize the recent advances in drug discovery of new small molecules in preclinical or clinical development for treating IBD that target biologically relevant pathways in mucosal inflammation. These include intracellular enzymes (Janus kinases, receptor interacting protein, phosphodiesterase 4, IκB kinase), integrins, G protein-coupled receptors (S1P, CCR9, CXCR4, CB2) and inflammasome mediators (NLRP3), etc. We will also discuss emerging evidence of a distinct mechanism of action, bromodomain-containing protein 4, an epigenetic regulator of pathways involved in the activation, communication, and trafficking of immune cells. We highlight their chemotypes, mode of actions, structure-activity relationships, characterizations, and their in vitro/in vivo activities and therapeutic potential. The perspectives on the relevant challenges, new opportunities, and future directions in this field are also discussed.

Therapeutic efficacy of rifaximin loaded tamarind gum polysaccharide nanoparticles in TNBS induced IBD model Wistar rats

Background

Rifaximin is a non-systemic antibiotic used in the treatment of inflammatory bowel disease (IBD). Antibiotics are demonstrating a significant role in the treatment of IBD by altering the dysbiotic colonic microbiota and decreases the immunogenic and inflammatory response in the patient population. Mucoadhesive colon targeted nanoparticles provide the site-specific delivery and extended stay in the colon. Since the bacteria occupy the lumen, spread over the surface of epithelial cells, and adhere to the mucosa, delivering the rifaximin as a nanoparticles with the mucoadhesive polymer enhances the therapeutic efficacy in IBD. The objective was to fabricate and characterize the rifaximin loaded tamarind gum nanoparticles and study the therapeutic efficacy in the TNBS-induced IBD model rats.

Materials and methods

The experimentation includes fabrication and characterization of drug excipient compatibility by FTIR. The fabricated nanoparticles were characterized for the hydrodynamic size and zeta potential by photon correlation spectroscopy and also analyzed by TEM. Selected best formulation was subjected to the therapeutic efficacy study in TNBS-induced IBD rats, and the macroscopic, microscopic and biochemical parameters were reported.

Results

The study demonstrated that the formulation TGN1 is best formulation in terms of nanoparticle characterization and hydrodynamic size which showed the hydrodynamic size of 171.4 nm and the zeta potential of -26.44 mV and other parameters such as TEM and drug release studies were also reported.

Conclusions

The therapeutic efficacy study revealed that TGN1 is efficiently reduced the IBD inflammatory conditions as compared to the TNBS control group and reference drug mesalamine group.

Saccharomyces boulardii Ameliorates Dextran Sulfate Sodium-Induced Ulcerative Colitis in Mice by Regulating NF-κB and Nrf2 Signaling Pathways

Saccharomyces boulardii (S. boulardii) is a probiotic yeast that is widely used to treat gastrointestinal disorders. The present study is aimed to explore the therapeutic effects of S. boulardii on dextran sulfate sodium- (DSS-) induced murine ulcerative colitis (UC) and illustrate the mechanisms of action. C57BL/6 mice were administered S. boulardii (10⁵ and 10⁷ CFU/ml, p.o.) for 3 weeks and then given DSS [2.5% (w/v)] for one week. Administration of S. boulardii prevented DSS-induced reduction in body weight, diarrhea, bloody feces, decreased colon length, and loss of histological structure. Moreover, S. boulardii protected the intestinal barrier by increasing the levels of tight junction proteins zona occludens-1 and Occludin and exerted immunomodulatory effects in DSS-induced mice. Furthermore, S. boulardii suppressed the colonic inflammation by reducing the levels of Interleukin-1β, Interleukin-6, and Tumor necrosis factor alpha and restored myeloperoxidase activity in mice exposed to DSS. S. boulardii also mitigated colonic oxidative damage by increasing the levels of antioxidant enzymes (superoxide dismutase, catalase, and heme oxygenase 1) and glutathione and decreasing malondialdehyde accumulation. Further studies identified that S. boulardii suppressed the nuclear translocation of nuclear factor kappa B (NF-κB) p65 subunit by decreasing IκKα/β levels, while promoted the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) in DSS-exposed mice. Collectively, S. boulardii possessed an appreciable therapeutic effect against the experimental mice model of UC. The protective mechanism of S. boulardii may involve inhibition of NF-κB-mediated proinflammatory signaling and activation of Nrf2-modulated antioxidant defense in addition to intestinal barrier protective and immunomodulatory effects.

Targeting Sphingosine-1-Phosphate Signaling in Immune-Mediated Diseases: Beyond Multiple Sclerosis

Sphingosine-1-phosphate (S1P) is a bioactive lipid metabolite that exerts its actions by engaging 5 G-protein-coupled receptors (S1PR1-S1PR5). S1P receptors are involved in several cellular and physiological events, including lymphocyte/hematopoietic cell trafficking. An S1P gradient (low in tissues, high in blood), maintained by synthetic and degradative enzymes, regulates lymphocyte trafficking. Because lymphocytes live long (which is critical for adaptive immunity) and recirculate thousands of times, the S1P-S1PR pathway is involved in the pathogenesis of immune-mediated diseases. The S1PR1 modulators lead to receptor internalization, subsequent ubiquitination, and proteasome degradation, which renders lymphocytes incapable of following the S1P gradient and prevents their access to inflammation sites. These drugs might also block lymphocyte egress from lymph nodes by inhibiting transendothelial migration. Targeting S1PRs as a therapeutic strategy was first employed for multiple sclerosis (MS), and four S1P modulators (fingolimod, siponimod, ozanimod, and ponesimod) are currently approved for its treatment. New S1PR modulators are under clinical development for MS, and their uses are being evaluated to treat other immune-mediated diseases, including inflammatory bowel disease (IBD), rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and psoriasis. A clinical trial in patients with COVID-19 treated with ozanimod is ongoing. Ozanimod and etrasimod have shown promising results in IBD; while in phase 2 clinical trials, ponesimod has shown improvement in 77% of the patients with psoriasis. Cenerimod and amiselimod have been tested in SLE patients. Fingolimod, etrasimod, and IMMH001 have shown efficacy in RA preclinical studies. Concerns relating to S1PR modulators are leukopenia, anemia, transaminase elevation, macular edema, teratogenicity, pulmonary disorders, infections, and cardiovascular events. Furthermore, S1PR modulators exhibit different pharmacokinetics; a well-established first-dose event associated with S1PR modulators can be mitigated by gradual up-titration. In conclusion, S1P modulators represent a novel and promising therapeutic strategy for immune-mediated diseases.

Role of sphingosine-1-phosphate receptors in vascular injury of inflammatory bowel disease

Sphingosine‐1‐phosphate receptors (S1PRs) have an impact on the intestinal inflammation of inflammatory bowel disease (IBD) by regulating lymphocyte migration and differentiation. S1PR modulators as an emerging therapeutic approach are being investigated for the treatment of IBD. However, the role of S1PRs in intestinal vessels has not drawn much attention. Intestinal vascular damage is one of the major pathophysiological features of IBD, characterized by increased vascular density and impaired barrier function. S1PRs have pleiotropic effects on vascular endothelial cells, including proliferation, migration, angiogenesis and barrier homeostasis. Mounting evidence shows that S1PRs are abnormally expressed on intestinal vascular endothelial cells in IBD. Unexpectedly, S1PR modulators may damage intestinal vasculature, for example increase intestinal bleeding; therefore, S1PRs are thought to be involved in the regulation of intestinal vascular function in IBD. However, little is understood about how S1PRs regulate intestinal vascular function and participate in the initiation and progression of IBD. In this review, we summarize the pathogenic role of S1PRs in and the underlying mechanisms behind the intestinal vascular injury in IBD in order for improving IBD practice including S1PR‐targeted therapies.

Long-Term Efficacy and Safety of Ozanimod in Moderately to Severely Active Ulcerative Colitis: Results From the Open-Label Extension of the Randomized, Phase 2 TOUCHSTONE Study

BACKGROUND AND AIMS

This analysis examined the long-term safety and efficacy of ozanimod in patients with moderately to severely active ulcerative colitis [UC] with ≥ 4 years of follow-up in the phase 2 TOUCHSTONE open-label extension [OLE].

METHODS

Patients receiving placebo or ozanimod HCl 0.5 mg or 1 mg during the double-blind period could enter the OLE [ozanimod HCl 1 mg daily]. Partial Mayo score [pMS] clinical response and remission were assessed through OLE week 200 and summarized descriptively using observed cases [OC] and non-responder imputation [NRI]. Endoscopy was required at OLE week 56 and the end of treatment. Parameters associated with endoscopy were summarized at weeks 56 and 104 [OC], and week 56 [NRI]. C-reactive protein and faecal calprotectin were assessed. Adverse events were monitored throughout the study.

RESULTS

Of 197 patients receiving double-blind treatment, 170 entered the OLE. Discontinuation rates were 28% at year 1 and 15-18% annually through year 4. Partial Mayo measures indicated clinical response and remission rates at OLE week 200 of 93.3% and 82.7%, respectively, using OC and 41% and 37% with the more conservative NRI analysis. At weeks 56 and 104, respectively, histological remission rates were 46.3% and 38.5%, and endoscopic improvement rates were 46.4% and 46.5% [OC]. No new safety signals were identified during ≥ 4 years of follow-up.

CONCLUSIONS

There was a high rate of continued study participation and long-term benefit with ozanimod HCl 1 mg daily based on clinical, histological and biomarker measures in patients with moderately to severely active UC in the TOUCHSTONE OLE. [NCT02531126].

Menthacarin attenuates experimental colitis

BACKGROUND

Peppermint oil and caraway oil are established remedies in gastroenterological medicine because of their spasmolytic/analgesic effects.

PURPOSE

We investigated whether Menthacarin, a combination of both oils, exerted anti-inflammatory effects in a dextran sodium sulphate (DSS, 2%) murine model of colitis.

STUDY DESIGN AND METHODS

C57BL/6 mice were orally administered Menthacarin in doses of 10, 30, 60, and 120 µg/g body weight (BW), and control mice received 0.2% agar, 10 µl/g BW, during 8 days of DSS-induced colitis. Colitis was monitored by BW measurements and colonoscopies. Colons of euthanised mice were excised for histological staining and ELISA measurements of the cytokines TNFα, IL-6, IL-10, IL-1β, and TGF-β.

RESULTS

Menthacarin-treated mice compared to controls showed improved macroscopical and microscopical parameters and lower BW loss during the course of colitis. Menthacarin changed the colonic cytokine profile towards a regulatory/anti-inflammatory phenotype.

CONCLUSION

Menthacarin attenuates experimental colitis and may be a promising add-on therapy for the treatment of IBD.

Mechanism of Huang-lian-Jie-du decoction and its effective fraction in alleviating acute ulcerative colitis in mice: Regulating arachidonic acid metabolism and glycerophospholipid metabolism

ETHNOPHARMACOLOGICAL RELEVANCE

Huang-lian-Jie-du decoction (HLJDD) is a traditional Chinese medicine prescription for clearing away heat, purging fire and detoxifying, which can be used to treat sepsis, stroke, Alzheimer's disease and gastrointestinal diseases. Our previous studies have shown that HLJDD can effectively alleviate acute ulcerative colitis (UC) in mice, and its n-butanol fraction (HLJDD-NBA) is the effective fraction. The aim of this study is to further investigate the mechanism of HLJDD and HLJDD-NBA in relieving UC in mice from a holistic perspective.

METHODS

The acute UC model of BABL/c mice was induced by 3.5% (w/v) dextran sodium sulfate drinking water. At the same time of modeling, HLJDD and HLJDD-NBA were given orally for treatment respectively. During the experiment, the clinical symptoms of mice were recorded and the physiological and biochemical indexes of mice were detected after the experiment. In addition, the plasma metabolites of mice in each group were detected and analyzed by ultra-high performance liquid chromatography quadrupole time of flight mass spectrometry and multivariate statistical analysis method. Then, the potential target metabolic pathway of drug intervention was screened through the enrichment analysis of differential metabolites. Finally, we use molecular simulation docking technology to further explore the molecular regulatory mechanism of HLJDD and HLJDD-NBA on potential target metabolic pathways.

RESULTS

HLJDD and HLJDD-NBA intervention can significantly reduce the disease activity index of UC mice, inhibit colon length shortening and pathological damage, and relieve the abnormal changes of physiological and biochemical parameters of UC mice. Moreover, HLJDD and HLJDD-NBA can significantly inhibit the metabolic dysfunction of UC mice by reversing the abnormal changes of 24 metabolites in UC mice, and the arachidonic acid metabolic pathway and glycerophospholipid metabolic pathway are the target metabolic pathways regulated by them. Further literature review and molecular simulation docking analysis showed that HLJDD and HLJDD-NBA may inhibit the disorder of arachidonic acid metabolism pathway and glycerophospholipid metabolism pathway by inhibiting COX-2 protein expression and PLA2, 5-LOX activity.

CONCLUSIONS

Our experiments revealed that HLJDD and HLJDD-NBA can alleviate UC of mice by regulating arachidonic acid metabolism and glycerophospholipid metabolism, which points out the direction for further research and development of HLJDD as a new anti-ulcer drug.

Huang-Lian-Jie-Du Decoction Ameliorates Acute Ulcerative Colitis in Mice via Regulating NF-κB and Nrf2 Signaling Pathways and Enhancing Intestinal Barrier Function

Evidence shows that intestinal inflammation, oxidative stress, and injury of mucosal barrier are closely related to the pathogenesis of ulcerative colitis (UC). Huang-lian-Jie-du Decoction (HLJDD) is a well-known prescription of traditional Chinese medicine with anti-inflammatory and antioxidative activities, which may be used to treat UC. However, its therapeutic effect and mechanism are still unclear. In this study, the UC model of BABL/c mice were established by DSS [3.5% (w/v)], and HLJDD was given orally for treatment at the same time. During the experiment, the clinical symptoms of mice were scored by disease activity index (DAI). Besides, the effects of HLJDD on immune function, oxidative stress, colon NF-κB and Nrf2 signaling pathway, and intestinal mucosal barrier function in UC mice were also investigated. The results showed that HLJDD could alleviate body weight loss and DAI score of UC mice, inhibit colonic shortening and relieve colonic pathological damage, and reduce plasma and colon MPO levels. In addition, HLJDD treatment significantly up-regulated plasma IL-10, down-regulated TNF-α and IL-1β levels, and inhibited the expression of NF-κB p65, p-IκKα/β, and p-IκBα proteins in the colon. Moreover, NO and MDA levels in colon tissues were significantly reduced after HLJDD treatment, while GSH, SOD levels and Nrf2, Keap1 protein expression levels were remarkably elevated. Additionally, HLJDD also protected intestinal mucosa by increasing the secretion of mucin and the expression of ZO-1 and occludin in colonic mucosa. These results indicate that HLJDD could effectively alleviate DSS-induced mice UC by suppressing NF-κB signaling pathway, activating Nrf2 signaling pathway, and enhancing intestinal barrier function.

Targeting Cytokine Signaling and Lymphocyte Traffic via Small Molecules in Inflammatory Bowel Disease: JAK Inhibitors and S1PR Agonists

The inflammatory Bowel diseases (IBDs) are a chronic, relapsing inflammatory diseases of the gastrointestinal tract with heterogeneous behavior and prognosis. The introduction of biological therapies including anti-TNF, anti-IL-12/23, and anti-integrins, has revolutionized the treatment of IBD, but these drugs are not universally effective. Due to the complex molecular structures of biologics, they are uniformly immunogenic. New discoveries concerning the underlying mechanisms involved in the pathogenesis of IBD have allowed for progress in the development of new treatment options. The advantage of small molecules (SMs) over biological therapies includes their lack of immunogenicity, short half-life, oral administration, and low manufacturing cost. Among these, the Janus Kinases (JAKs) inhibition has emerged as a novel strategy to modulate downstream cytokine signaling during immune-mediated diseases. These drugs target various cytokine signaling pathways that participate in the pathogenesis of IBD. Tofacitinib, a JAK inhibitor targeting predominantly JAK1 and JAK3, has been approved for the treatment of ulcerative colitis (UC), and there are other specific JAK inhibitors under development that may be effective in Crohn's. Similarly, the traffic of lymphocytes can now be targeted by another SM. Sphingosine-1-phosphate receptor (S1PR) agonism is a novel strategy that acts, in part, by interfering with lymphocyte recirculation, through blockade of lymphocyte egress from lymph nodes. S1PR agonists are being studied in IBD and other immune-mediated disorders. This review will focus on SM drugs approved and under development, including JAK inhibitors (tofacitinib, filgotinib, upadacitinib, peficitinib) and S1PR agonists (KRP-203, fingolimod, ozanimod, etrasimod, amiselimod), and their mechanism of action.

Selective Tyk2 inhibitors as potential therapeutic agents: a patent review (2015-2018)

INTRODUCTION

Tyrosine kinase 2 (Tyk2) is a non-receptor tyrosine-protein kinase, an enzyme that in humans is encoded by the TYK2 gene. Tyk2, together with three other family subtypes, namely, Jak1, Jak2, and Jak3, belong to the JAK family. Before 2014, far more publications and patents appeared in public domain attributing to the development of selective Jak2 and Jak3 inhibitors than those for selective Tyk2 and Jak1 inhibitors.

AREAS COVERED

This review sought to give an overview of patents related to small molecule selective Tyk2 inhibitors published from 2015 to 2018. The article also covers clinical activities of small molecule selective Tyk2 inhibitors in recent years.

EXPERT OPINION

As a key component of the JAK-STAT signaling pathway, Tyk2 regulates INFα, IL12, and IL23. Selective inhibition of Tyk2 can provide pharmacological benefits in the treatment of many diseases such as psoriasis, systemic lupus erythematosus (SLE), inflammatory bowel disease (IBD), rheumatoid arthritis (RA), cancer, and diabetes. The selectivity against other Jak family subtypes (such as Jak2) is crucial in order to minimize the potential side effects and to maximize the desired pharmacological effects. In this context, this review of recent selective Tyk2 inhibitor patents may prove valid, interesting, and promising within the therapeutic paradigm.

Cell Trafficking Interference in Inflammatory Bowel Disease: Therapeutic Interventions Based on Basic Pathogenesis Concepts

After 20 years of successful targeting of pro-inflammatory cytokines for the treatment of IBD, an alternative therapeutic strategy has emerged, based on several decades of advances in understanding the pathogenesis of IBD. The targeting of molecules involved in leukocyte traffic has recently become a safe and effective alternative. With 2 currently approved drugs (ie, natalizumab, vedolizumab) and several others in phase 3 trials (eg, etrolizumab, ozanimod, anti-MAdCAM-1), the blockade of trafficking molecules has firmly emerged as a new therapeutic era for IBD. We discuss the targets that have been explored in clinical trials: chemokines and its receptors (eg, IP10, CCR9), integrins (eg, natalizumab, AJM300, vedolizumab, and etrolizumab), and its endothelial ligands (MAdCAM-1, ICAM-1). We also discuss a distinct strategy that interferes with lymphocyte recirculation by blocking lymphocyte egress from lymph nodes (small molecule sphingosine-phosphate receptor [S1PR] agonists: fingolimod, ozanimod, etrasimod, amiselimod). Strategies on the horizon include additional small molecules, allosteric inhibitors that specifically bind to the active integrin form and nanovectors that allow for the use of RNA interference in the quest to modulate pro-inflammatory leukocyte trafficking in IBD.

Implementation of Mass Cytometry as a Tool for Mechanism of Action Studies in Inflammatory Bowel Disease

Background

Novel therapeutics for inflammatory bowel disease (IBD) are under development, yet mechanistic readouts at the tissue level are lacking. Techniques to assess intestinal immune composition could represent a valuable tool for mechanism of action (MOA) studies of novel drugs. Mass cytometry enables analysis of intestinal inflammatory cell infiltrate and corresponding molecular fingerprints with unprecedented resolution. Here, we aimed to optimize the methodology for isolation and cryopreservation of cells from intestinal tissue to allow for the potential implementation of mass cytometry in MOA studies.

Methods

We investigated key technical issues, including minimal tissue requirements, cell isolation protocols, and cell storage, using intestinal biopsies and peripheral blood from healthy individuals. High-dimensional mass cytometry was employed for the analyses of biopsy-derived intestinal cellular subsets.

Results

Dithiothreitol and mechanical dissociation decreased epithelial cell contamination and allowed for isolation of adequate cell numbers from 2 to 4 colonic or ileal biopsies (6 × 104±2 × 104) after a 20-minute collagenase digestion, allowing for reliable detection of most major immune cell subsets. Biopsies and antibody-labeled mononuclear cells could be cryopreserved for later processing and acquisition (viability > 70%; P < 0.05).

Conclusions

Mass cytometry represents a unique tool for deep immunophenotyping intestinal cell composition. This technique has the potential to facilitate analysis of drug actions at the target tissue by identifying specific cellular subsets and their molecular signatures. Its widespread implementation may impact not only IBD research but also other gastrointestinal conditions where inflammatory cells play a role in pathogenesis.

Characteristics of cytomegalovirus enterocolitis in patients with or without inflammatory bowel diseases

OBJECTIVES

Cytomegalovirus (CMV) disease is more common in immunocompromised patients but may occur in people with normal immune function. In addition, CMV enterocolitis can aggravate inflammatory bowel diseases (IBD), but there was little knowledge of differences in clinical and endoscopic features of CMV enterocolitis between patients with IBD and without IBD. The aim of this study was to determine the difference in clinical implication in CMV enterocolitis between the IBD patients and non-IBD patients.

METHODS

This was a retrospective study of 82 patients with CMV enterocolitis based on the pathologic findings at two tertiary referral hospitals from 2003 to 2013. Clinical and endoscopic characteristics and clinical course were analyzed according to the presence of IBD.

RESULTS

Of the 82 patients, 25 (30.5%) had IBD and 57 (69.5%) did not have IBD. Hematochezia was more common in IBD patients (84.0% vs. 35.1%; p = .001), but fever and positive CMV antigenemia were more common in non-IBD patients (50.9% vs. 12.0%; p = .001; 54.4% vs. 28.0; p = .027). Endoscopic findings showed more ulcer with inflammation in IBD patients (68.0% vs. 35.2%; p = .005). Sixty-four patients were treated with antiviral agents and 12 patients who did not receive antiviral agents recovered spontaneously. All naturally healed patients were in normal immune status.

CONCLUSIONS

Hematochezia is more common in IBD patients and fever/CMV antigenemia is more common in patients without IBD. In patients without IBD, the natural resolution of CMV enterocolitis is expected at least in normal immune function.

Inflammatory Bowel Diseases and Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols: An Overview

Inflammatory bowel diseases (IBDs) are mainly represented by ulcerative colitis and Crohn's disease, and the increase in the incidence tends to follow the rapid industrialization and lifestyle of modern societies. FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) consist of molecules that are poorly absorbed in the small intestine and are fermented by bacteria in the colon leading to symptoms such as bloating, flatulence, diarrhea, and abdominal pain. Reduction of the ingestion of FODMAP could reduce the symptoms and improve the quality of life. This review aimed to summarize some important aspects of IBD and evaluate the effects of this diet on this inflammatory condition. Studies including the term FODMAP (and similar terms) and IBD were selected for this review (MEDLINE database was used PubMed/PMC). A low FODMAP diet may be an effective tool to the management of the common abdominal symptoms in patients with functional gastrointestinal symptoms once these molecules trigger these symptoms. This diet may also reduce the expression of pro-inflammatory markers such as C-reactive protein and fecal calprotectin and may interfere with the microbiome and its metabolites. The use of a low FODMAP diet can bring benefits to the IBD patients, but may also modify their nutritional status. Thus it should be utilized in appropriated conditions, and dietary supplements should be necessary to avoid deficiencies that could be caused by a low FODMAP diet over long periods. We suggest that further investigations are required to elucidate when and how to apply the FODMAP diet in IBD patients.