1,3-Diphenylpropenone ameliorates TNBS-induced rat colitis through suppression of NF-κB activation and IL-8 induction

Development of trans-Chalcone loaded pectin/casein biodegradable microcapsules: Efficacy improvement in the management of experimental colitis

Improved therapies for inflammatory bowel diseases are sorely needed. Novel therapeutic agents and the development of controlled release systems for targeted tissue delivery are interesting approaches to overcome these barriers. We investigated the activity of trans-chalcone (T) in acetic acid-induced colitis in mice and developed, characterized, and determined the therapeutic effect of pectin/casein polymer microcapsules containing T (MT) in a colitis mouse model. In vitro, compound release was achieved in simulated intestinal fluid but not in the simulated gastric fluid. In vivo, since T at the dose of 3 mg/kg but not 0.3 mg/kg ameliorated colitis, we next tested the effects of MT at 0.3 mg/kg (non-effective dose). MT, but not free T at 0.3 mg/kg, significantly improved colitis outcomes such as neutrophil recruitment, antioxidant capacity, cytokine production, and NF-kB activation. This translated into reduced macro and microscopic damage in the colon. T release from the microcapsules is mediated by a pH-dependent and pectinase-regulated mechanism that provide controlled and prolonged release of T. Moreover, MT lowered the required dose for T therapeutic effect, indicating that could be a suitable pharmaceutical approach to colitis treatment. This is the first demonstration that T or MT is effective at reducing the signs of colitis.

Protection against ulcerative colitis and colorectal cancer by evodiamine via anti‑inflammatory effects

Evodiamine (Evo) is an alkaloid that can be extracted from the berry fruit Evodia rutaecarpa and has been reported to exert various pharmacological effects, such as antidiarrheal, antiemetic and antiulcer effects. In vivo, the potential effects of Evo were investigated in a mouse model of dextran sodium sulfate (DSS)‑induced ulcerative colitis (UC) and in adenomatous polyposis coli (Apc)MinC/Gpt C57BL/6 mice with colorectal cancer (CRC), where the latter harbours a point‑mutation in the Apc gene. Evo suppressed the degree of weight loss and colon shortening induced by DSS, decreased the disease activity index value and ameliorated the pathological alterations in the colon of mice with UC as examined via H&E staining of colon tissues. In addition, Evo decreased the number and size of colonic tumors in ApcMinC/Gpt mice. Proteomics (colon tissues), ELISA (colon tissues and serum) and western blotting (colon tissues) results revealed that Evo inhibited NF‑κB to mediate the levels of various cytokines, including, in the DSS‑induced UC model, IL‑1β, IL‑2, IL‑6, IL‑8, TNF‑α, IFN‑γ (ELISA of colon tissues and serum), NF‑κB, IKKα+β, IκBα, S100a9, TLR4 and MyD88 (western blotting of colon tissues), and, in the colorectal cancer model, IL‑1β, IL‑2, IL‑6, IL‑15, IL‑17, IL‑22, TNF‑α (ELISA of colon tissues and serum), NF‑κB, IKKα+β, IκBα and S100a9 (western blotting of colon tissues), to achieve its anti‑inflammatory and antitumor effects. In vitro, Evo also reduced the viability of the colon cancer cell line SW480, inhibited mitochondrial membrane potential (MMP detection), caused G2/M‑phase arrest (cell cycle detection) and suppressed the translocation of phosphorylated‑NF‑κB from the cytoplasm into the nucleus (immunofluorescence of p‑NF‑κB). Theoretical evidence (MD simulations) suggest that Evo may bind to the ordered domain (α‑helix) of NF‑κB to influence this protein. The protein secondary structure changes were analyzed by the cpptraj module in Amber. In addition, these data provide experimental evidence that Evo may be an effective agent for treating UC and CRC.

An Update of Research Animal Models of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a group of chronic disorders that includes two main disease forms, Crohn's disease, and ulcerative colitis. The understanding of the intestinal inflammation occurring in IBD has been immeasurably advanced by the development of the now numerous murine models of intestinal inflammation. The usefulness of this research tool in IBD arises from a convergence of underlying genetic susceptibility, immune system dysfunction, environmental factors, and shifts in gut microbiota. Due to the multifactorial feature of these diseases, different animal models have been used to investigate the underlying mechanisms and develop potential therapeutic strategies. The results of preclinical efficacy studies often inform the progression of therapeutic strategies. This review describes the distinct feature and limitations of each murine IBD model and discusses the previous and current lessons from the IBD models.

Linagliptin mitigates experimental inflammatory bowel disease in rats by targeting inflammatory and redox signaling

AIMS

Dipeptidyl peptidase-4 (DPP-4) has been involved in the pathogenesis of inflammatory bowel diseases (IBD), yet the underlying mechanisms remain inconclusive. The present study aimed to investigate the potential of linagliptin, a potent/selective DPP-4 inhibitor with marked anti-inflammatory actions, to attenuate trinitrobenzene sulfonic acid (TNBS)-evoked colitis in rats; an experimental model of IBD, and the implicated molecular mechanisms. This may add to the clinical utility of linagliptin for the management of patients with coexisting IBD and diabetes mellitus. Notably, no former studies have linked JAK2/STAT3, HMGB1/NF-κB, and Nrf2/HO-1 signaling in TNBS-evoked colitis.

MATERIALS AND METHODS

Western blotting and ELISA were used to determine the levels of target signals.

KEY FINDINGS

Administration of linagliptin (1.5 mg/kg; p.o.) mitigated the colitis severity via diminishing the disease activity index, colon weight/length ratio, and macroscopic scores. Linagliptin also lowered the colonic histologic scores and leukocyte invasion. Notably, linagliptin inhibited the colonic DPP-4 activity and upregulated the expression of intestinotrophic GLP-2 without incurring hypoglycemia in animals. Linagliptin curbed inflammation through the suppression of colonic IL-6, TNF-α, and myeloperoxidase and upregulation of IL-10. It also inhibited the IL-6/JAK2/STAT3 pathway via downregulating p-JAK2/JAK2 and p-STAT3/STAT3 protein expression and HMGB1/RAGE/NF-κB cascade through lowering HMGB1, RAGE, and p-NF-κB p65/NF-κB p65 protein expression. In the context of mucosal oxidative stress, linagliptin diminished lipid peroxides and augmented GSH, GPx, and total antioxidant capacity. It also activated Nrf2/HO-1 pathway via upregulating Nrf2 and HO-1 protein expression.

SIGNIFICANCE

Linagliptin shows a promise for the management of IBD via targeting IL-6/JAK2/STAT3, HMGB1/RAGE/NF-κB, and Nrf2/HO-1 pathways.

Activation of autophagy and suppression of apoptosis by dapagliflozin attenuates experimental inflammatory bowel disease in rats: Targeting AMPK/mTOR, HMGB1/RAGE and Nrf2/HO-1 pathways

Dapagliflozin, a selective sodium-glucose co-transporter 2 (SGLT2) inhibitor, has featured marked anti-inflammatory effects in murine models of myocardial infarction, renal injury, and neuroinflammation. Yet, its potential impact on the pathogenesis of inflammatory bowel diseases (IBD) has not been previously investigated. The presented study aimed to explore the prospect of dapagliflozin to mitigate 2,4,6 trinitrobenzene sulfonic acid (TNBS)-induced rat colitis model which recapitulates several features of the human IBD. The molecular mechanisms pertaining to the dynamic balance between autophagy/apoptosis and colon injury were delineated, particularly, AMPK/mTOR, HMGB1/RAGE/NF-κB and Nrf2/HO-1 pathways. The colon tissues were examined using immunoblotting, ELISA, and histopathology. Dapagliflozin (0.1, 1 and 5 mg/kg; p.o.) dose-dependently mitigated colitis severity as manifested by suppression of the disease activity scores, macroscopic damage scores, colon weight/length ratio, histopathologic perturbations, and inflammatory markers. More important, dapagliflozin enhanced colonic autophagy via upregulating Beclin 1 and downregulating p62 SQSTM1 protein expression. In this context, dapagliflozin activated the AMPK/mTOR pathway by increasing the p-AMPK/AMPK and lowering the p-mTOR/mTOR ratios, thereby, favoring autophagy. Moreover, dapagliflozin dampened the colonic apoptosis via lowering the caspase-3 activity, cleaved caspase-3 expression, and Bax/Bcl-2 ratio. Furthermore, dapagliflozin attenuated the HMGB1/RAGE/NF-κB pathway via lowering HMGB1, RAGE, and p-NF-κBp65 protein expression. Regarding oxidative stress, dapagliflozin lowered the oxidative stress markers and augmented the Nrf2/HO-1 pathway. Together, the present study reveals, for the first time, the ameliorative effect of dapagliflozin against experimental colitis via augmenting colonic autophagy and curbing apoptosis through activation of AMPK/mTOR and Nrf2/HO-1 pathways and suppression of HMGB1/RAGE/NF-κB cascade.

Inhibition of colitis by ring-modified analogues of 6-acetamido-2,4,5-trimethylpyridin-3-ol

6-Aminopyridin-3-ol scaffold has shown an excellent anti-inflammatory bowel disease activity. Various analogues with the scaffold were synthesized in pursuit of the diversity of side chains tethering on the C(6)-position. Structure-activity relationship among the analogues was investigated to understand the effects of the side chains and their linkers on their anti-inflammatory activities. In this study, structural modification moved beyond side chains on the C(6)-position and reached to pyridine ring itself. It expedited us to synthesize diverse ring-modified analogues of a representative pyridine-3-ol, 6-acetamido-2,4,5-trimethylpyridin-3-ol (9). In the evaluation of compounds on their inhibitory actions against TNF-α-induced adhesion of monocytic cells to colonic epithelial cells, an in vitro model mimicking colon inflammation, the effects of compounds 9, 17, and 19 were greater than tofacitinib, an orally available anti-colitis drug, and compound 17 showed the greatest activity. In addition, TNF-α-induced angiogenesis, which permits more inflammatory cell migration into inflamed tissues, was significantly blocked by compounds 17 and 19 in a concentration-dependent manner. In the comparison of in vivo therapeutic effects of compounds 9, 17, and 19 on dextran sulfate sodium (DSS)-induced colitis in mice, compound 17 was the most potent and efficacious, and compound 19 was better than compound 9 which showed a similar degree of inhibitory effect to tofacitinib. Taken together, it seems that either the trimethyl system or the hydroxyl group on the pyridinol ring is essential to the activity. This finding might become a new milestone in the development of pyridinol-based anti-inflammatory bowel disease agents.

Protective effects of fermented rice extract on ulcerative colitis induced by dextran sodium sulfate in mice

Ulcerative colitis (UC) is a chronic inflammatory bowel disease (IBD), characterized by the gut mucosal ulceration. Growing evidence indicates that dysregulation of immune response to the commensal microbiota involves the pathogenesis of IBD. Previous studies have demonstrated the favorable probiotic effects of fermented rice extracts through triple fermentation with Saccharomyces cerevisiae and Weissella cibaria (FRe). Thus, the therapeutic potential of FRe for UC was examined. Dextran sodium sulfate UC mice model was orally administered distilled water as a control, sulfasalazine, or FRe at 300, 200, and 100 mg/kg, once a day for a week. The UC control exhibited body weight loss, bloody stools, and colonic shortening. However, the FRe, especially at 300 mg/kg, led to a reduction in weight loss, disease activity index scores, and colon weight, and an increase in colorectal length. The histopathological analyses revealed mild changes involved in the colonic crypt and mucosal damages in the FRe groups, along with inhibited inflammation. Indeed, the FRe reduced neutrophil infiltration and production of proinflammatory cytokines (i.e., tumor necrosis factor-α, interleukin-6/-8). This was accompanied by the down-regulation of nuclear factor-kappa B. The gene expression responsible for the intestinal barrier integrity (i.e., Zonna occludens-1/-2, Claudin-1, Occludin, Mucin-1/-2) was up-regulated in the FRe groups. In addition, the FRe reduced lipid peroxidation and enhanced antioxidant activity. Interestingly, the microbiota dysbiosis was attenuated in the FRe groups, and the number of beneficial bacteria, Lactobacilli and Bifidobacteria, was increased. It suggests that the FRe potently ameliorate UC as a functional food.

Effect of a bioactive product SEL001 from Lactobacillus sakei probio65 on gut microbiota and its anti-colitis effects in a TNBS-induced colitis mouse model

This study underpins the therapeutic potential of SEL001, a bioactive product isolated from Lactobacillus sakei probio65, in terms of its anti-inflammatory properties and its effect on gut-microbiota in a TNBS-induced ulcerative colitis mouse model. Ulcerative colitis was developed in mice by intra rectal administration of trinitrobenzene sulfonic acid. Bioactive product SEL001 (50 mg/kg b.w.) was administered orally. Myeloperoxidase activity was measured using 3,3', 5,5'-tetramethylbenzidine. The entire colon was sampled for post-mortem clinical assessment. Colonic injury was assessed through histological and histomorphometric examinations. The 454 pyrosequencing and QIIME pipeline were used for gut microbiota analysis and statistical analysis were conducted using R. mRNA extraction from colon tissue and RT-PCR approaches were employed to determine the changes in the level of specific biomarker genes associated with UC. The results depict that SEL001 significantly lowered pro-inflammatory cytokines, including CD4, TNF-α, and interleukin-6. Examination of clinical and histopathological traits revealed that SEL001 was effective and potent in reducing the inflammatory signatures of UC to a similar extent as did by the standard drug mesalamine (5-ASA). Pyro-sequencing 16S data revealed that the reduction in the major member of phylum Firmicutes, which has been previously associated with a higher risk of UC. The SEL001, an anti-inflammatory bioactive product originated from a probiotic strain L. sakei probio65 could be an alternative therapeutic agent for treatment of UC.

(E)-3-(3-methoxyphenyl)-1-(2-pyrrolyl)-2-propenone displays suppression of inflammatory responses via inhibition of Src, Syk, and NF-κB

(E)-3-(3-methoxyphenyl)-1-(2-pyrrolyl)-2-propenone (MPP) is an aldol condensation product resulting from pyrrole-2-carbaldehyde and m- and p- substituted acetophenones. However, its biological activity has not yet been evaluated. Since it has been reported that some propenone-type compounds display anti-inflammatory activity, we investigated whether MPP could negatively modulate inflammatory responses. To do this, we employed lipopolysaccharide (LPS)-stimulated macrophage-like RAW264.7 cells and examined the inhibitory levels of nitric oxide (NO) production and transcriptional activation, as well as the target proteins involved in the inflammatory signaling cascade. Interestingly, MPP was found to reduce the production of NO in LPS-treated RAW264.7 cells, without causing cytotoxicity. Moreover, this compound suppressed the mRNA levels of inflammatory genes, such as inducible NO synthase (iNOS) and tumor necrosis factor (TNF)-α. Using luciferase reporter gene assays performed in HEK293 cells and immunoblotting analysis with nuclear protein fractions, we determined that MPP reduced the transcriptional activation of nuclear factor (NF)-κB. Furthermore, the activation of a series of upstream signals for NF-κB activation, composed of Src, Syk, Akt, and IκBα, were also blocked by this compound. It was confirmed that MPP was able to suppress autophosphorylation of overexpressed Src and Syk in HEK293 cells. Therefore, these results suggest that MPP can function as an anti-inflammatory drug with NF-κB inhibitory properties via the suppression of Src and Syk.

A review on chemical-induced inflammatory bowel disease models in rodents

Ulcerative colitis and Crohn's disease are a set of chronic, idiopathic, immunological and relapsing inflammatory disorders of the gastrointestinal tract referred to as inflammatory bowel disorder (IBD). Although the etiological factors involved in the perpetuation of IBD remain uncertain, development of various animal models provides new insights to unveil the onset and the progression of IBD. Various chemical-induced colitis models are widely used on laboratory scale. Furthermore, these models closely mimic morphological, histopathological and symptomatical features of human IBD. Among the chemical-induced colitis models, trinitrobenzene sulfonic acid (TNBS)-induced colitis, oxazolone induced-colitis and dextran sulphate sodium (DSS)-induced colitis models are most widely used. TNBS elicits Th-1 driven immune response, whereas oxazolone predominantly exhibits immune response of Th-2 phenotype. DSS-induced colitis model also induces changes in Th-1/Th-2 cytokine profile. The present review discusses the methodology and rationale of using various chemical-induced colitis models for evaluating the pathogenesis of IBD.

Serotonin regulates innate immune responses of colon epithelial cells through Nox2-derived reactive oxygen species

Changes in serotonin (5-hydroxytryptamine, 5-HT) content in the gut of patients with inflammatory bowel disease (IBD) and animal models of colitis suggest an important role of 5-HT in the pathogenesis of IBD. In this study, we examined the role and mechanism of action of 5-HT in the inflammatory response of colon epithelial cells in vitro and in vivo. In colon epithelial cells (CCD 841, HT-29, Caco-2), direct application of 5-HT induced production of reactive oxygen species (ROS) and monocyte-epithelial adhesion, an initial event of inflammation, which were blocked not only by 5-HT receptor antagonists (tropisetron, RS39604, and SB269970), antioxidants (ascorbic acid, apocynin), and various inhibitors of NADPH oxidase (DPI), CREB (KG-501), and NF-κB (PDTC), but also by transfection with Nox2 siRNA. Nox2-derived production of ROS corresponded with the rapid and brief activation of Rac. In addition, 5-HT induced Nox2, p67(phox), and Duox2 without altering the level of Nox1 or Duox1 in colon epithelial cells, and silencing of Nox2 suppressed 5-HT-induced Duox2 increase. 5-HT also induced an increase in the expression of MCP-1, IL-8, and ICAM-1 and a decrease in E-cadherin expression. Exogenous application of 5-HT to rat colon through the rectum caused a minimal level of inflammation, which was demonstrated by histological examination, MPO activity, and inflammatory cytokine induction. However, 5-HT combined with a low dose of 2,4,6-trinitrobenzene sulfonic acid (TNBS), the level of which caused a minimal level of colitis, exaggerated colon inflammation accompanied by much more enhanced induction of inflammatory cytokines, IL-6, IL-8, and MCP-1, indicating that colon epithelial cells directly exposed to 5-HT are primed toward inflammation. In the colon at the lesion site, treatment with 5-HT resulted in an increase in the level of epithelial Nox2 but not of constitutively expressed Nox1, which is the opposite result of TNBS treatment. Furthermore, 5-HT treatment of Nox2-knockout mice did not induce colon inflammation, in contrast to 5-HT-treated wild-type mice. The results demonstrate that colon epithelial cells directly exposed to 5-HT are primed for inflammatory reactions, which is an important innate immune response, and the underlying mechanism for the priming is associated with Nox2-activated signaling pathways, including ERK/p38 MAPK, NF-κB, and CREB.

Cyclic chalcone analogue KRP6 as a potent modulator of cell proliferation: an in vitro study in HUVECs

In the present investigation a novel series of chalcone analogues were synthesized and evaluated for their anti-proliferative activity in human umbilical vein endothelial cells (HUVECs). Among 14 tested compounds, chalcone analogue (E)-3-(2'-methoxybenzylidene)-4-chromanone (KRP6) exhibited the most potent activity with IC50 19 μM. Moreover, HUVECs exhibited divergent, even opposing concentration-dependent responses to KRP6. This compound was the most potent inhibitor of cell proliferation and extracellular matrix formation (fibronectin and type IV collagen) at higher concentrations (20-50 μM). In contrast, KRP6 stimulated the compensatory increase in proliferative activity including extracellular matrix formation at low concentrations (1, 10 μM). KRP6 concentration-dependently modulated phosphorylation of Akt and mitogen-activated protein kinases such as extracellular signal-regulated kinase-1/-2 and p38 kinase, suggesting that these pathways play a role in the effect mediated by this compound. In addition, we found a selective effect on activated endothelial cells, in particular with resting endothelial cells. In conclusion, KRP6 is a potent modulator of selected steps of the angiogenic process in vitro. Accordingly, further in vivo research should be performed to facilitate its use in clinical practice.

Low molecular weight fucoidan ameliorating the chronic cisplatin-induced delayed gastrointestinal motility in rats

Delayed gastrointestinal (GI) motility is frequent adverse effect associated with chemotherapy due to oxidative stress, activation of 5-HT3 receptors or serotonin releases from enterochromaffin cells. Fucoidan, extracts from brown seaweeds, has been showed antioxidant related favorable pharmacological activities including digestive tract protective effects. Low molecular weight fucoidan (LMF) obtained by acid hydrolysis of high molecular weight fucoidan has been showed more favorable bioactivities. This study was conducted to determine whether or not LMF can prevent delayed GI motility induced by the antineoplastic drug cisplatin chronically administered, once per week for five consecutive weeks. LMF ameliorating the chronic cisplatin treatment related body weight decreases, delayed GI motility, and enhanced the antioxidant defense systems. In addition, LMF also inhibited the cisplatin treatment related GI gastrin and serotonin changes, including enzyme activities involved in serotonin metabolism and enterochromaffin cells. The overall effects of LMF 10mg/kg were similar to that of ondansetron 1mg/kg, a serotonin 5-HT3 receptor antagonist. The present results supported that LMF have favorable ameliorating effect on the delayed GI motility induced by chemotherapy, modulated the GI enterochromaffin cells, serotonin and gastrin-producing cells with antioxidant effects. This effect of LMF may help improve accompanying digestive disorders by chemotherapy.