The role of bidirectional communication between the adipokines and the endogenous opioid system in an experimental mouse model of colitis-associated colorectal cancer.

BACKGROUND: Colorectal cancer (CRC) is one of the leading causes of death globally. Multiple factors may contribute to the pathogenesis of CRC, including the abnormalities in the functioning of the endogenous opioid system (EOS) or adiponectin-related signaling. The aim of our study was to evaluate if differences in the expression of opioid receptors (ORs) influence the development of CRC and if modulation of adiponectin receptors using AdipoRon, a selective AdipoR1 receptor agonist, affects colorectal carcinogenesis. METHODS: Naltrexone, an opioid receptor antagonist, was injected intraperitoneally every second day for 2 weeks, at the dose of 1 mg/kg in healthy Balb/C mice to induce changes in ORs expression. CRC was induced by a single intraperitoneal injection of azoxymethane (AOM) and the addition of dextran sodium sulfate (DSS) into drinking water in three-week cycles. The development of CRC was assessed using macro- and microscopic scoring and molecular analysis (RT qPCR, ELISA) after 14 weeks. RESULTS: Naltrexone significantly increased the mRNA expression of Oprm1, Oprd1, and Oprk1 in the mouse colon and in the brain (non-significantly). The pretreatment of mice with naltrexone aggravated the course of CRC (as indicated by tumor area, colon thickness, and spleen weight). The level of circulatory adiponectin was lowered in mice with CRC and increased in the colon as compared with healthy mice. The ß-endorphin level was increased in the plasma of mice with CRC and decreased in the colon as compared to healthy mice. AdipoRon, AdipoR1 agonist, worsened the CRC development, and pretreatment with naltrexone enhanced this negative effect in mice. CRC did not affect the expression of the Adipor1 gene, but the Adipor1 level was increased in mice pretreated with naltrexone (AOM/DSS and healthy mice). AdipoRon did not influence the expression of opioid receptors at the mRNA level in the colon of mice with CRC. The mRNA expression of Ptgs2, Il6, Nos2, Il1b, Il18, Gsdmd, and Rela was increased in mice with CRC as compared to the healthy colon. AdipoRon significantly decreased mRNA expression of Ptgs2, Il6, Il1b, and Il18 as compared to CRC mice. CONCLUSION: EOS and adiponectin-related signaling may play a role in the pathogenesis of CRC and these systems may present some additivity during carcinogenesis.

Long non-coding RNAs - SNHG6 emerge as potential marker in colorectal cancer.

Colorectal cancer (CRC) ranks among the leading cancers in terms of incidence and mortality in the Western world. Currently, there are no sufficient diagnostic markers that would enable an early diagnosis and efficient therapy. Unfortunately, a significant number of new CRC cases is detected in late stages, with distant metastases, therefore, new therapeutic approaches, which would alleviate the prognosis for advanced stages of CRC, are highly in demand. SNHG6 belongs to the group of long non-coding RNAs, which are a larger entity of RNAs consisting of >200 nucleotides. SNHG6 is expressed mainly in the cell cytoplasm, where it acts as a regulator of numerous processes: modulation of crucial protein hubs; sponging miRNAs and upregulating the expression of their target mRNAs; and interacting with various cellular pathways including TGF-ß/Smad and Wnt/ß-catenin. SNHG6 is an oncogene, substantially overexpressed in CRC tissues and cancerous cell lines as compared to healthy samples. Its overexpression is associated with higher grade, lymphovascular invasion and tumor size. Taking into consideration the role of SNHG6 in the colorectal tumorigenesis, invasion and metastasis, we summarized its role in CRC and conclude that it could serve as a potential biomarker in CRC diagnosis and prognosis assessment.

GDF11 as a friend or an enemy in the cancer biology?

The Growth and Differential Factor 11 (GDF11) is a recently discovered representative of Transforming Growth Factor ß superfamily. The highest expression of GDF11 is detected in the nervous system, bladder, seminal vesicles and muscles whereas the lowest in the testis, liver or breast. GDF11 role in physiology is still not clear. GDF11 is a crucial factor in embryogenesis, cell cycle control and apoptosis, inasmuch it mainly targets cell retain stemness features, managing to the cell differentiation and the maturation. GDF11 is entangled in lipid metabolism, inflammatory processes and aging. GDF11 is strongly related to carcinogenesis and its expression in tumors is intruded. GDF11 can promote cancer growth in the colon or inhibit the cell proliferation in breast cancer. The aberrated expression is probably allied with the impaired maturation. In this article we summarized an impact of GDF11 on the tumor cells and review the all attitudes connecting GDF11 with carcinogenesis.

The role of GDF11 during inflammation - An overview.

GDF11 (Growth differentiation factor 11) is a newly discovered member of family of transforming growth factors-ß. Its crucial role was confirmed in physiology, i.e. embryogenesis due to its involvement in bone formation, skeletogenesis and it is essential to stating skeletal pattern. GDF11 is described as a rejuvenating and anti-aging molecule, that could even restore functions. Beside embryogenesis, GDF11 participates in the process of inflammation and carcinogenesis. An anti-inflammatory effect of GDF11 was found in experimental colitis, psoriasis and arthritis. Current data regarding liver fibrosis and renal injury indicate that GDF11 may act as pro-inflammatory agent. In this review, we describe its involvement in regulation of acute and chronic inflammatory disorders.

Increased GPR35 expression in human colorectal and pancreatic cancer samples: A preliminary clinical validation of a new biomarker.

BACKGROUND: G protein-coupled receptor 35 (GPR35) is involved in carcinogenesis; however, limited experimental data are available on its actual expression in patients with colorectal cancer (CRC) and pancreatic adenocarcinoma (PDAC). OBJECTIVES: We aimed to measure the relative expression of GPR35 in samples from patients with CRC or PDAC. MATERIAL AND METHODS: Using real-time polymerase chain reaction (RT-PCR), we have examined GPR35 expression in surgery samples from 40 CRC and 17 PDAC patients, and performed analysis of the results. RESULTS: The analysis of GPR35 expression in patients with CRC revealed correlations between relative GPR35 mRNA expression and several tumor characteristics, with statistical significance for higher American Joint Committee on Cancer (AJCC) stages, T stages and histological grades. GPR35 expression was significantly higher in tumor samples compared to the paired healthy samples collected from the same patient. Similar, although not statistically significant trends were found in PDAC tumor samples for sex (lower expression in women) and for samples with no nodal involvement (lower expression). Samples with higher tumor T stages and higher histological grades or considered inoperable had higher GPR35 expression. CONCLUSIONS: We have identified correlations which confirm our expectation of high GPR35 expression in CRC and PDAC. Our findings suggest the prognostic value of GPR35 testing in patients with an increased risk of CRC or PDAC development, and warrant further clinical confirmation.

The role of kappa opioid receptors in immune system - An overview.

Opioids are one of the most effective anti-nociceptive agents used in patients with cancer pain or after serious surgery in most countries. The endogenous opioid system participates in pain perception, but recently its role in inflammation was determined. κ-opioid receptors (KOP receptors), a member of the opioid receptor family, are expressed in the central and peripheral nervous system as well as on the surface of different types of immune cells, e.g. T cells, B cells and monocytes. In this review, we focused on the involvement of KOP receptors in the inflammatory process and described their function in a number of conditions in which the immune system plays a key role (e.g. inflammatory bowel disease, arthritis, subarachnoid hemorrhage, vascular dysfunction) and inflammatory pain. We summed up the application of known KOP ligands in pathophysiology and we aimed to shed new light on KOP receptors as important elements during inflammation.

SMYD2 targets RIPK1 and restricts TNF-induced apoptosis and necroptosis to support colon tumor growth.

SMYD2 is a histone methyltransferase, which methylates both histone H3K4 as well as a number of non-histone proteins. Dysregulation of SMYD2 has been associated with several diseases including cancer. In the present study, we investigated whether and how SMYD2 might contribute to colorectal cancer. Increased expression levels of SMYD2 were detected in human and murine colon tumor tissues compared to tumor-free tissues. SMYD2 deficiency in colonic tumor cells strongly decreased tumor growth in two independent experimental cancer models. On a molecular level, SMYD2 deficiency sensitized colonic tumor cells to TNF-induced apoptosis and necroptosis without affecting cell proliferation. Moreover, we found that SMYD2 targeted RIPK1 and inhibited the phosphorylation of RIPK1. Finally, in a translational approach, pharmacological inhibition of SMYD2 attenuated colonic tumor growth. Collectively, our data show that SMYD2 is crucial for colon tumor growth and inhibits TNF-induced apoptosis and necroptosis.

Colonic inflammation induces changes in glucose levels through modulation of incretin system.

BACKGROUND: The role of the incretin hormone, glucagon-like peptide (GLP-1), in Crohn's disease (CD), is still poorly understood. The aim of this study was to investigate whether colitis is associated with changes in blood glucose levels and the possible involvement of the incretin system as an underlaying factor. METHODS: We used a murine model of colitis induced by 2,4,6-trinitrobenzenesulfonic acid (TNBS). Macroscopic and microscopic score and expression of inflammatory cytokines were measured. The effect of colitis on glucose level was studied by measurement of fasting glucose and GLP-1, dipeptidyl peptidase IV (DPP IV) levels, prohormone convertase 1/3 (PC 1/3) and GLP-1 receptor (GLP-1R) expression in mice. We also measured the level of GLP-1, DPP IV and expression of glucagon (GCG) and PC 1/3 mRNA in serum and colon samples from healthy controls and CD patients. RESULTS: Fasting glucose levels were increased in animals with colitis compared to controls. GLP-1 was decreased in both serum and colon of mice with colitis in comparison to the control group. DPP IV levels were significantly increased in serum, but not in the colon of mice with colitis as compared to healthy animals. Furthermore, PC 1/3 and GLP-1R expression levels were increased in mice with colitis as compared to controls. In humans, no differences were observed in fasting glucose level between healthy subjects and CD patients. GLP-1 levels were significantly decreased in the serum. Interestingly, GLP-1 level was significantly increased in colon samples of CD patients compared to healthy subjects. No significant differences in DPP IV levels in serum and colon samples were observed between groups. CONCLUSIONS: Changes in the incretin system during colitis seem to contribute to the impaired glucose levels. Differences in incretin levels seem to be modulated by degrading enzyme DPP-IV and PC 1/3. Obtained results suggest that the incretin system may become a novel therapeutic approach in the treatment of CD.

AdipoRon, an Orally Active, Synthetic Agonist of AdipoR1 and AdipoR2 Receptors Has Gastroprotective Effect in Experimentally Induced Gastric Ulcers in Mice.

INTRODUCTION: Adiponectin is a hormone secreted by adipocytes, which exhibits insulin-sensitizing and anti-inflammatory properties and acts through adiponectin receptors: AdipoR1 and AdipoR2. The aim of the study was to evaluate whether activation of adiponectin receptors AdipoR1 and AdipoR2 with an orally active agonist AdipoRon has gastroprotective effect and to investigate the possible underlying mechanism. METHODS: We used two well-established mouse models of gastric ulcer (GU) induced by oral administration of EtOH (80% solution in water) or diclofenac (30 mg/kg, p.o.). Gastroprotective effect of AdipoRon (dose 5 and 50 mg /kg p.o) was compared to omeprazole (20 mg/kg p.o.) or 5% DMSO solution (control). Clinical parameters of gastroprotection were assessed using macroscopic (gastric lesion area) and microscopic (evaluation of the gastric mucosa damage) scoring. To establish the molecular mechanism, we measured: myeloperoxidase (MPO), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) activities; glutathione (GSH) level; and IL-1ß, adenosine monophosphate-activated protein kinase (AMPK), and phosphorylated AMPK expression in gastric tissue. RESULTS: AdipoRon produced a gastroprotective effect in both GU mouse models as evidenced by significantly lower macroscopic and microscopic damage scores. AdipoRon exhibited anti-inflammatory effect by reduction in MPO activity and IL-1ß expression in the gastric tissue. Moreover, AdipoRon induced antioxidative action, as demonstrated with higher GSH levels, and increased SOD and GPX activity. CONCLUSIONS: Activation of AdipoR1 and AdipoR2 using AdipoRon reduced gastric lesions and enhanced cell response to oxidative stress. Our data suggest that AdipoR1 and AdipoR2 activation may be an attractive therapeutic strategy to inhibit development of gastric ulcers.

Blockade of fructose transporter protein GLUT5 inhibits proliferation of colon cancer cells: proof of concept for a new class of anti-tumor therapeutics.

BACKGROUND: Despite the fact that colorectal cancer (CRC) is one of the most commonly diagnosed cancers in men and women, its current treatment remains unsatisfactory and therefore novel studies proposing new approaches are necessary. A high sugar diet is believed to promote carcinogenesis. Fructose is absorbed from the gastrointestinal tract by members of the glucose transporter family-GLUT. The aim of the study was to characterize the expression of GLUT5 at mRNA level in CRC patients. Moreover, our goal was to elucidate the molecular role of GLUT5 in CRC and assess whether GLUT5 inhibitor may affect the viability of colon cancer cells. METHODS: The expression of GLUT5 at mRNA level was characterized based on 30 samples from resected colorectal cancers and 30 healthy colonic mucosa specimens from surgical margins. The inhibitory effect of N-[4-(methylsulfonyl)-2-nitrophenyl]-1,3-benzodioxol-5-amine (MSBNA) was assessed on a colon cancer cell line, HT-29, and normal colon epithelium cells-CCD 841 CoN Cells. RESULTS: GLUT5 expression was found in 96.7% of cancer specimens and only in 53.3% of healthy mucosa fragments. In cancer tissue, real-time PCR analysis showed almost 2, fivefold (p< 0.001) increase of GLUT5 mRNA expression level compared with the healthy intestinal mucosa. GLUT5 inhibitor, MSNBA (10 µM) significantly decreased the viability of colon cancer cells, while barely affected the viability of normal colon epithelium cells. CONCLUSIONS: Our study suggests that a strong focus should be put on GLUT5 and its inhibitors for both diagnostic and therapeutic purposes in CRC.

Novel selective agonist of GPR18, PSB-KK-1415 exerts potent anti-inflammatory and anti-nociceptive activities in animal models of intestinal inflammation and inflammatory pain.

BACKGROUND: GPR18 is a recently deorphanized receptor which was reported to act with several endogenous cannabinoid ligands. Here, we aimed to describe the role of GPR18 in intestinal inflammation and inflammatory pain. METHODS: The anti-inflammatory activity of selective GPR18 agonist, PSB-KK-1415, and antagonist, PSB-CB5, was characterized in semi-chronic and chronic mouse models of colitis induced by 2,4,6-trinitrobenzenesulfonic acid (TNBS). The extent of inflammation was evaluated based on the macroscopic and microscopic scores, quantification of myeloperoxidase (MPO) activity, and Western blot analyses of tumor necrosis factor-α (TNF-α) and interleukin-6 in colonic tissue. The expression of GPR18 in colonic samples from patients with Crohn's disease (CD) was quantified using real-time PCR. The anti-nociceptive potential of the agonist in intestinal inflammation was evaluated in the mouse model of inflammatory pain. KEY RESULTS: In semi-chronic colitis, PSB-KK-1415 reduced macroscopic score (1.79 ± 0.22 vs. 2.61 ± 0.48), expression of TNF-α (1.89 ± 0.36 vs. 2.83 ± 0.64), and microscopic score (5.00 ± 0.33 vs. 6.45 ± 0.40), all compared to mice with colitis. In chronic colitis, PSB-KK-1415 decreased macroscopic score (3.33 ± 1.26 vs. 4.00 ± 1.32) and MPO activity (32.23 ± 8.51 vs. 41.33 ± 11.64) compared to inflamed mice. In the mouse model of inflammatory pain, PSB-KK-1415 decreased the number of pain-induced behaviors in both, controls (32.60 ± 2.54 vs. 58.00 ± 6.24) and inflamed mice (60.83 ± 2.85 vs. 85.00 ± 5.77) compared to animals without treatment with PSB-KK-1415 (P < 0.005 for both). Lastly, we showed an increased expression of GPR18 in CD patients compared to healthy controls (3.77 ± 1.46 vs. 2.38 ± 0.66, p = 0.87). CONCLUSIONS & INFERENCES: We showed that GPR18 is worth considering as a potential treatment target in intestinal inflammation and inflammatory pain.

New insights into molecular pathways in colorectal cancer: Adiponectin, interleukin-6 and opioid signaling.

Colorectal cancer (CRC) is one of the most common cause of death among neoplasms around the world. The environmental factors, like diet and obesity, are crucial in CRC pathogenesis by creating cancer-favorable microenvironment and hormonal changes. Adiponectin, the adipose tissue-specific hormone, is generally considered to negatively correlate with CRC development. The interleukin 6 (IL-6) is one of the most important pro-inflammatory cytokine connected with CRC, which is strongly inflammation-associated. The opioids are variable group substantially correlated with cancers - the endogenous opioids affect immune system and cell cycle including proliferation and cell death whereas exogenous opioids are leading clinically used analgesics in terminal cancer patients. In this review we discuss the involvement of adiponectin, IL-6 and opioids in CRC pathogenesis, their link with obesity, possible cross-talk and potential novel therapeutic approach in CRC treatment.

Cyclic derivative of morphiceptin Dmt-cyclo-(D-Lys-Phe-D-Pro-Asp)-NH2(P-317), a mixed agonist of MOP and KOP opioid receptors, exerts anti-inflammatory and anti-tumor activity in colitis and colitis-associated colorectal cancer in mice.

Endogenous opioid system is involved in the maintenance of the intestinal homeostasis. Recently, we proved that stimulation of opioid receptors using P-317, a cyclic morphiceptin analog, resulted in the alleviation of acute colitis in mice. The aim of the current study was to assess the effect of P-317 during colitis and colitis-associated colorectal cancer in mice. Colitis was induced by addition of dextran sodium sulfate (DSS) into drinking water. Colitis-associated colorectal cancer was induced by a single intraperitoneal injection of azoxymethane (AOM) and subsequent addition of DSS into drinking water (week 2, 5, 8). During macroscopic damage evaluation the samples were collected and used for biochemical (MPO activity assay), molecular (qPCR and western blot) and histological studies. In experimental colitis, P-317 induced an anti-inflammatory response as indicated by macroscopic and microscopic scores. In the colitis-associated colorectal cancer model, a significant difference in colorectal tumor development was observed between vehicle- and P-317-treated mice. P-317 decreased the total number of colonic tumors and inhibited MPO activity. Hematoxylin and eosin staining confirmed anti-tumor activity of P-317. The expression of TNF-α was decreased in P-317-treated mice as compared to the vehicle-treated group. P-317 decreased proliferation as well as ß-catenin expression in tumors. P-317, a mixed MOP and KOP receptor agonist, induced an anti-inflammatory response in experimental colitis and decreased tumor development in colitis-associated colorectal cancer in mice.

Visualization of Estrogen Receptors in Colons of Mice with TNBS-Induced Crohn's Disease using Immunofluorescence.

Crohn's disease is the most diagnosed type of inflammatory bowel disease. Chronic inflammation developing in the intestine leads to peristalsis disorder and damage of intestinal mucosa and seems to be associated with an increased risk of colon neoplastic transformation. Accumulating evidence indicates that estrogens and estrogen receptors affect not only hormone-sensitive tissues, but also other tissues not directly related to estrogens, such as the lungs or colon. Here, we describe the protocol for the successful immunofluorescence staining of estrogen receptors in colon obtained from a murine model of TNBS-induced Crohn's disease. A detailed protocol for the induction of Crohn's disease in mice and intestine preparation is provided as well as a step-by-step immunohistochemical procedure using formalin-fixed paraffin-embedded intestine sections. The described methods are not only useful for estrogen receptor detection and estrogen signaling investigation in vivo but can also be applied to for other proteins which may be involved in the development of colitis.

Opioids in Cancer Development, Progression and Metastasis: Focus on Colorectal Cancer.

OPINION STATEMENT: So far, opioids have been successfully used to reduce cancer pain in patients in order to improve their quality of life. However, the use of opioids leads to numerous side effects such as constipation, drowsiness, nausea, itching, increased sweating and hormonal changes. In this review, we described the action of opioids in several molecular pathways significant for maintenance of the intestinal homeostasis including the impact on the intestinal epithelium integrity, changes in microbiome composition, modulation of the immune system or induction of apoptosis and inhibition of angiogenesis. We summed up the role of individual opioids in the processes involved in the growth and development of cancer and elucidated if targeting opioid receptors may constitute novel therapeutic option in colon cancer.

G protein-coupled estrogen receptor mediates anti-inflammatory action in Crohn's disease.

Estrogens exert immunomodulatory action in many autoimmune diseases. Accumulating evidence highlights the meaningful impact of estrogen receptors in physiology and pathophysiology of the colon. However, the significance of G protein-coupled estrogen receptor (GPER) on Crohn's disease (CD), one of the inflammatory bowel disease (IBD) types, is still elusive. Our study revealed GPER overexpression at the mRNA and protein levels in patients with CD. To evaluate the effects of GPER activation/inhibition on colitis development, a murine 2, 4, 6-trinitrobenzene sulfonic acid (TNBS)-induced model of CD was used. We showed that activation of GPER reduces mortality, improves macroscopic and microscopic scores and lowers C-reactive protein (CRP) level. The impact of estrogen signaling on the suppression of the intestinal inflammation was proved by immunohistochemistry. It was demonstrated that GPER activation is accompanied by modulation of extracellular-signal regulated kinase (ERK) signaling pathway and expression level of genes involved in signal transmission and immune response as well as the expression of some microRNAs (miR-145, miR-148-5p and miR-592). Our study revealed that the membrane-bound estrogen receptor GPER mediates anti-inflammatory action and seems to be a potent therapeutic target in maintaining remission in CD.

Enkephalinase inhibitors, potential therapeutics for the future treatment of diarrhea predominant functional gastrointestinal disorders.

The endogenous opioid system (EOS) is considered being a crucial element involved in the pathophysiology of irritable bowel syndrome (IBS) as it regulates gastrointestinal (GI) homeostasis through modulation of motility and water and ion secretion/absorption. Along with opioid receptors (ORs), the following components of EOS can be distinguished: 1. endogenous opioid peptides (EOPs), namely enkephalins, endorphins, endomorphins and dynorphins, and 2. peptidases, which regulate the metabolism (synthesis and degradation) of EOPs. Enkephalins, which are δ-opioid receptors agonists, induce significant effects in the GI tract as they act as potent pro-absorptive neurotransmitters. The action of enkephalins and other EOPs is limited, since EOPs are easily and rapidly inactivated by a natural metalloendopeptidase (enkephalinase/neprilysin) and aminopeptidase N. Studies show that the activity of EOPs can be enhanced by inhibition of these enzymes. In this review, we discuss the antidiarrheal and antinociceptive potential of enkephalinase inhibitors. Furthermore, our review is to answer the question whether enkephalinase inhibitors may be helpful in the future treatment of diarrhea predominant functional GI disorders.

Antinociceptive potency of enkephalins and enkephalinase inhibitors in the mouse model of colorectal distension-proof-of-concept.

Irritable bowel syndrome (IBS) is a chronic disease characterized by abdominal pain and changes in bowel habits. Patients with IBS comprise a significant portion of attendants at the outpatient clinics. Targeting intestinal opioid receptors was found successful in alleviating pain and diarrhea-two major symptoms of IBS. In this study, we aimed to evaluate a novel potential pharmacological option: the use of enkephalinase inhibitors in therapy of visceral pain occurring in the course of IBS. We thus assessed the antinociceptive efficacy of enkephalins: Leu-enkephalin and Met-enkephalin, and enkephalinase inhibitors: opiorphin and sialorphin in the mouse model of visceral pain induced by colorectal distension. Leu-enkephalin, Met-enkephalin, and sialorphin, but not opiorphin, at the dose of 1 mg/kg injected subcutaneously potently decreased the visceromotor response to colon distension as compared to control. To conclude, enkephalinase inhibitors are worth being considered as potential therapeutics in patients with chronic abdominal pain and/or changed bowel habits, that is, suffering from IBS.

New Peptide Inhibitor of Dipeptidyl Peptidase IV, EMDB-1 Extends the Half-Life of GLP-2 and Attenuates Colitis in Mice after Topical Administration.

Protease inhibition has become a possible new approach in inflammatory bowel disease (IBD) therapy. A serine exopeptidase, dipeptidyl peptidase IV (DPP IV), is responsible for the inactivation of incretin hormone, glucagon-like peptide 2 (GLP-2), a potent stimulator of intestinal epithelium regeneration and growth. Recently, we showed that the novel peptide analog of endomorphin-2, Tyr-Pro-D-ClPhe-Phe-NH2 (EMDB-1) is a potent blocker of DPP IV and has an inhibitory effect on gastrointestinal (GI) smooth muscle contractility. The aim of this study was to characterize the anti-inflammatory effect and mechanism of action of EMDB-1 in the mouse GI tract. We used two models of experimental colitis (induced by TNBS and DSS). The anti-inflammatory effect of EMDB-1 was assessed by the determination of macroscopic score, ulcer score, colonic wall thickness, as well as myeloperoxidase activity. Additionally, we measured the expression of GLP-2, GLP2R, and DPP IV in the colon of control and colitic animals treated with the test compound. The expression of GLP-2 and GLP2R in the serum and colon of IBD patients and healthy control subjects has been assessed. We showed that EMDB-1 elevates the half-life of GLP-2 in vitro and attenuates acute, semichronic, and relapsing TNBS as well as DSS-induced colitis in mice after topical administration. The anti-inflammatory action of EMDB-1 is associated with changes in the level of colonic GLP-2 but not DPP IV expression. Our results validate DPP IV as a pharmacological target for the anti-IBD drugs, and its inhibitors based on natural substrates, such as EMDB-1, have the potential to become valuable anti-inflammatory therapeutic agents.