Vidofludimus inhibits colonic interleukin-17 and improves hapten-induced colitis in rats by a unique dual mode of action

Signaling effect, combinations, and clinical applications of triciribine

Triciribine (TCN) is a tricyclic nucleoside. Its synthesis was first described in 1971. Subsequent studies have indicated that TCN plays a role in inhibiting DNA synthesis and was revealed to possess a higher selectivity for Akt. Although a single dose of TCN demonstrated limited activity in solid tumors at the clinical level, combinations of TCN with various agents, such as specific inhibitors, tyrosine kinase inhibitor dasatinib, ErbB inhibitor tipifarnib, IGF1-R inhibitor NVP-AEW541, mTORC1 inhibitor RAD-001, TNF-related apoptosis-inducing ligand, PPARγ agonist, 1,25(OH)2D3, gemcitabine, and paclitaxel, have been reported to be efficient against various malignancies such as pancreatic, breast, prostate cancer, insulinoma, gut neuroendocrine tumor, and hepatocellular carcinoma at the preclinical level. Other than malignancies, through Akt inhibition activity, TCN has also been demonstrated potential for treating lung injuries, including those encountered in COVID-19 infections.

A Patent Review of Human Dihydroorotate Dehydrogenase (hDHODH) Inhibitors as Anticancer Agents and their Other Therapeutic Applications (1999-2022)

Highly proliferating cells, such as cancer cells, are in high demand of pyrimidine nucleotides for their proliferation, accomplished by de novo pyrimidine biosynthesis. The human dihydroorotate dehydrogenase (hDHODH) enzyme plays a vital role in the rate-limiting step of de novo pyrimidine biosynthesis. As a recognised therapeutic target, hDHODH plays a significant role in cancer and other illness. In the past two decades, small molecules as inhibitors hDHODH enzyme have drawn much attention as anticancer agents, and their role in rheumatoid arthritis (RA), and multiple sclerosis (MS). In this patent review, we have compiled patented hDHODH inhibitors published between 1999 and 2022 and discussed the development of hDHODH inhibitors as anticancer agents. Therapeutic potential of small molecules as hDHODH inhibitors for the treatment of various diseases, such as cancer, is very well recognised. Human DHODH inhibitors can rapidly cause intracellular uridine monophosphate (UMP) depletion to produce starvation of pyrimidine bases. Normal cells can better endure a brief period of starvation without the side effects of conventional cytotoxic medication and resume synthesis of nucleic acid and other cellular functions after inhibition of de novo pathway using an alternative salvage pathway. Highly proliferative cells such as cancer cells do not endure starvation because they are in high demand of nucleotides for cell differentiation, which is fulfilled by de novo pyrimidine biosynthesis. In addition, hDHODH inhibitors produce their desired activity at lower doses rather than a cytotoxic dose of other anticancer agents. Thus, inhibition of de novo pyrimidine biosynthesis will create new prospects for the development of novel targeted anticancer agents, which ongoing preclinical and clinical experiments define. Our work brings together a comprehensive patent review of the role of hDHODH in cancer, as well as various patents related to the hDHODH inhibitors and their anticancer and other therapeutic potential. This compiled work on patented DHODH inhibitors will guide researchers in pursuing the most promising drug discovery strategies against the hDHODH enzyme as anticancer agents.

Vidofludimus inhibits porcine reproductive and respiratory syndrome virus infection by targeting dihydroorotate dehydrogenase

Porcine reproductive and respiratory syndrome virus (PRRSV) infection has caused huge economic losses in global swine industry over the last 37 years. PRRSV commercial vaccines are not effective against all epidemic PRRSV strains. In this study we performed a high-throughput screening (HTS) of an FDA-approved drug library, which contained 2339 compounds, and found vidofludimus (Vi) could significantly inhibits PRRSV replication in Marc-145 cells and primary porcine alveolar macrophages (PAMs). Compounds target prediction, molecular docking analysis, and target protein interference assay showed that Vi interacts with dihydroorotate dehydrogenase (DHODH), a rate-limiting enzyme in the de novo pyrimidine synthesis pathway. Furthermore, PRRSV infection was restored in the presence of excess uridine and cytidine which promote pyrimidine salvage, or excess orotate which is the product of DHODH in the de novo pyrimidine biosynthesis pathway, thus confirming that the antiviral effect of Vi against PRRSV relies on the inhibition of DHODH. In addition, Vi also has antiviral activity against Seneca virus A (SVA), encephalomyocarditis virus (EMCV), porcine epidemic diarrhea virus (PEDV), and pseudorabies virus (PRV) in vitro. These findings should be helpful for developing a novel prophylactic and therapeutic strategy against PRRSV and other swine viral infections.

The activity and mechanism of vidofludimus as a potent enzyme inhibitor against NDM-1-positive E. coli

New Delhi metallo-β-lactamase-1 (NDM-1) is the most important and prevalent enzyme among all metallo-β-lactamases. NDM-1 can hydrolyze almost all-available β-lactam antibiotics including carbapenems, resulting in multidrug resistance, which poses an increasing clinical threat. However, there is no NDM-1 inhibitor approved for clinical treatment. Therefore, identifying a novel and potential enzyme inhibitor against NDM-1-mediated infections is an urgent need. In this study, vidofludimus was identified as a potential NDM-1 inhibitor by structure-based virtual screening and an enzyme activity inhibition assay. Vidofludimus significantly inhibited NDM-1 hydrolysis activity with a significant dose-dependent effect. When the vidofludimus concentration was 10 μg/ml, the inhibition rate and 50% inhibitory concentration were 93.3% and 13.8 ± 0.5 μM, respectively. In vitro, vidofludimus effectively restored the antibacterial activity of meropenem against NDM-1-positive Escherichia coli (E. coli), and the minimum inhibitory concentration of meropenem was decreased from 64 μg/ml to 4 μg/ml, a 16-fold reduction. The combination of vidofludimus and meropenem showed a significant synergistic effect with a fractional inhibitory concentration index of 0.125 and almost all the NDM-1-positive E. coli were killed within 12 h. Furthermore, the synergistic therapeutic effect of vidofludimus and meropenem in vivo was evaluated in mice infected with NDM-1 positive E. coli. Compared with the control treatment, vidofludimus combined with meropenem significantly improved the survival rate of mice infected with NDM-1-positive E. coli (P < 0.05), decreased the white blood cell count, the bacterial burden and inflammatory response induced by NDM-1-positive E. coli (P < 0.05), and alleviated histopathological damage in infected mice. It was demonstrated by molecular dynamic simulation, site-directed mutagenesis and biomolecular interaction that vidofludimus could interact directly with the key amino acids (Met67, His120, His122 and His250) and Zn²⁺ in the active site of NDM-1, thereby competitively inhibiting the hydrolysis activity of NDM-1 on meropenem. In summary, vidofludimus holds promise as anNDM-1 inhibitor, and the combination of vidofludimus and meropenem has potential as a therapeutic strategy for NDM-1-mediated infections.

Safety, Tolerability and Pharmacokinetics of Vidofludimus calcium (IMU-838) After Single and Multiple Ascending Oral Doses in Healthy Male Subjects

Background and Objective

Vidofludimus is a potent and selective inhibitor of human mitochondrial enzyme dihydroorotate dehydrogenase (DHODH). The clinical efficacy and safety profile of vidofludimus has been analyzed in patients suffering from rheumatoid arthritis and Crohn’s disease and ulcerative colitis. In previous sudies, hematuria at higher doses occurred in close temporal relationship to vidofludimus administration and appeared to be dose related. The present report describes the results from two phase 1 studies conducted in healthy male subjects to investigate the safety, tolerability and pharmacokinetics after single and multiple ascending (SAD and MAD) oral doses of IMU-838 (vidofludimus calcium, tablets containing a specific polymorph). The effect of food on the pharmacokinetics of IMU-838 was also assessed in the SAD study.

Methods

In the SAD study, 12 subjects received single doses of IMU-838 under fasting (10–40 mg) or fed (10 mg) condition in an open-label, partial parallel group design. In the MAD study, 52 subjects received multiple doses of IMU-838 (30–50 mg) in a double-blind, placebo-controlled, parallel group design.

Results

IMU-838 showed dose-proportional pharmacokinetics after single and multiple oral dosing in both SAD and MAD studies. IMU-838 was well absorbed after single daily doses. Food did not impact the pharmacokinetics of IMU-838. The accumulation factor for multiple daily dosing was approximately 2. Steady-state concentrations were reached within about 6–8 days for 30–50 mg groups. The geometric mean plasma half-life of IMU-838 at steady state was approximately 30 h, which supports its use for once-daily dosing regimen. Single and multiple oral doses of IMU-838 were safe and well tolerated.

Conclusion

Overall, oral IMU-838 was generally well tolerated in SAD and MAD studies in healthy subjects over a wide dose range of 10–50 mg. IMU-838 was well absorbed after single daily doses. IMU-838 showed dose proportional pharmacokinetics after single and multiple oral dosing.

Electronic supplementary material

The online version of this article (10.1007/s13318-020-00623-7) contains supplementary material, which is available to authorized users.

DHODH inhibition synergizes with DNA-demethylating agents in the treatment of myelodysplastic syndromes

Dihydroorotate dehydrogenase (DHODH) catalyzes a rate-limiting step in de novo pyrimidine nucleotide synthesis. DHODH inhibition has recently been recognized as a potential new approach for treating acute myeloid leukemia (AML) by inducing differentiation. We investigated the efficacy of PTC299, a novel DHODH inhibitor, for myelodysplastic syndrome (MDS). PTC299 inhibited the proliferation of MDS cell lines, and this was rescued by exogenous uridine, which bypasses de novo pyrimidine synthesis. In contrast to AML cells, PTC299 was inefficient at inhibiting growth and inducing the differentiation of MDS cells, but synergized with hypomethylating agents, such as decitabine, to inhibit the growth of MDS cells. This synergistic effect was confirmed in primary MDS samples. As a single agent, PTC299 prolonged the survival of mice in xenograft models using MDS cell lines, and was more potent in combination with decitabine. Mechanistically, a treatment with PTC299 induced intra-S-phase arrest followed by apoptotic cell death. Of interest, PTC299 enhanced the incorporation of decitabine, an analog of cytidine, into DNA by inhibiting pyrimidine production, thereby enhancing the cytotoxic effects of decitabine. RNA-seq data revealed the marked downregulation of MYC target gene sets with PTC299 exposure. Transfection of MDS cell lines with MYC largely attenuated the growth inhibitory effects of PTC299, suggesting MYC as one of the major targets of PTC299. Our results indicate that the DHODH inhibitor PTC299 suppresses the growth of MDS cells and acts in a synergistic manner with decitabine. This combination therapy may be a new therapeutic option for the treatment of MDS.

DHODH and cancer: promising prospects to be explored

Human dihydroorotate dehydrogenase (DHODH) is a flavin-dependent mitochondrial enzyme catalyzing the fourth step in the de novo pyrimidine synthesis pathway. It is originally a target for the treatment of the non-neoplastic diseases involving in rheumatoid arthritis and multiple sclerosis, and is re-emerging as a validated therapeutic target for cancer therapy. In this review, we mainly unravel the biological function of DHODH in tumor progression, including its crucial role in de novo pyrimidine synthesis and mitochondrial respiratory chain in cancer cells. Moreover, various DHODH inhibitors developing in the past decades are also been displayed, and the specific mechanism between DHODH and its additional effects are illustrated. Collectively, we detailly discuss the association between DHODH and tumors in recent years here, and believe it will provide significant evidences and potential strategies for utilizing DHODH as a potential target in preclinical and clinical cancer therapies.

A comprehensive drug repurposing study for COVID19 treatment: novel putative dihydroorotate dehydrogenase inhibitors show association to serotonin-dopamine receptors

Dihydroorotate dehydrogenase (DHODH) is a key enzyme required for de novo pyrimidine synthesis and it is suggested as a target for COVID19 treatment due to high pyrimidine demand by the virus replication in the infected host cells as well as its proven effect of blocking of cytokine release by the immune cells to prevent inflammation leading to acute respiratory distress. There are a number of clinical trials underway for COVID19 treatment using DHODH inhibitors; however, there are only a small number of known DHODH antagonists available for testing. Here, we have applied a methodology to identify DHODH antagonist candidates, and compared them using in silico target prediction tools. A large set of 7900 FDA-approved and clinical stage drugs obtained from DrugBank were docked against 20 different structures DHODH available in PDB. Drugs were eliminated according to their predicted affinities by Autodock Vina. About 28 FDA-approved and 79 clinical trial ongoing drugs remained. The mode of interaction of these molecules was analyzed by repeating docking using Autodock 4 and DS Visualiser. Finally, the target region predictions of 28 FDA-approved drugs were determined through PASS and SwissTargetPrediction tools. Interestingly, the analysis of in silico target predictions revealed that serotonin-dopamine receptor antagonists could also be potential DHODH inhibitors. Our candidates shared a common attribute, a possible interaction with serotonin-dopamine receptors as well as other oxidoreductases, like DHODH. Moreover, the Bruton Tyrosine Kinase-inhibitor acalabrutunib and serotonin-dopamine receptor inhibitor drugs on our list have been found in the literature that have shown to be effective against Sars-CoV-2, while the path of activity is yet to be identified. Identifying an effective drug that can suppress both inflammation and virus proliferation will play a crucial role in the treatment of COVID. Therefore, we suggest experimental investigation of the 28 FDA-approved drugs on DHODH activity and Sars-CoV-2 virus proliferation. Those who are found experimentally effective can play an important role in COVID19 treatment. Moreover, we suggest investigating COVID19 case conditions in patients using schizophrenia and depression drugs.

Design, synthesis, molecular modeling, and biological evaluation of acrylamide derivatives as potent inhibitors of human dihydroorotate dehydrogenase for the treatment of rheumatoid arthritis

Human dihydroorotate dehydrogenase (DHODH) is a viable target for the development of therapeutics to treat cancer and immunological diseases, such as rheumatoid arthritis (RA), psoriasis and multiple sclerosis (MS). Herein, a series of acrylamide-based novel DHODH inhibitors as potential RA treatment agents were designed and synthesized. 2-Acrylamidobenzoic acid analog 11 was identified as the lead compound for structure-activity relationship (SAR) studies. The replacement of the phenyl group with naphthyl moieties improved inhibitory activity significantly to double-digit nanomolar range. Further structure optimization revealed that an acrylamide with small hydrophobic groups (Me, Cl or Br) at the 2-position was preferred. Moreover, adding a fluoro atom at the 5-position of the benzoic acid enhanced the potency. The optimization efforts led to potent compounds 42 and 53‒55 with IC50 values of 41, 44, 32, and 42 nmol/L, respectively. The most potent compound 54 also displayed favorable pharmacokinetic (PK) profiles and encouraging in vivo anti-arthritic effects in a dose-dependent manner.

IBD and Bile Acid Absorption: Focus on Pre-clinical and Clinical Observations

Inflammatory bowel disease (IBD) causes chronic inflammation affecting the GI tract. It is classified as consisting of Crohn’s Disease (CD) and Ulcerative Colitis (UC). Bile Acid absorption is altered in both pre-clinical models of Inflammatory Bowel Disease (IB) and in human IBD. The bile acid transporter apical sodium dependent bile acid transporter (ASBT) showed decreased expression in rats with TNBS colitis. Decreased ASBT expression has also been described in murine, canine and rabbit models of intestinal inflammation. Human IBD studies have shown that an inflamed ileum can interrupt enterohepatic recirculation of bile acid, which could be due to inflammatory cytokine induced repression of the ASBT promoter. There are different hypotheses as to why ASBT is downregulated during CD. In addition, one study has demonstrated the beneficial effect of a glucocorticoid on ASBT expression, when treating IBD. Our aim in this paper was to systematically review various aspects of bile acid malabsorption in animal models of intestinal inflammation, as well as in IBD.

Repositioning an Immunomodulatory Drug Vidofludimus as a Farnesoid X Receptor Modulator With Therapeutic Effects on NAFLD

Non-alcoholic fatty liver disease (NAFLD) has become the most common chronic liver disorder, and yet with no pharmacological treatment approved worldwide. The repositioning of old drugs provides a safe approach for drug development. Vidofludimus, an inhibitor for dihydroorotate dehydrogenase (DHODH) for the treatment of autoimmune disorders, is herein uncovered as a novel modulator for farnesoid X receptor (FXR) by biochemical and crystallographic analysis. We further revealed that vidofludimus exerts in vivo therapeutic effects on dextran sodium sulfate (DSS)-induced colitis in an FXR-dependent manner. Notably, vidofludimus also possesses remarkable beneficial effects in reducing NAFLD by targeting FXR, which may represent a unique approach in developing the treatment for NAFLD. Our findings not only reveal a promising template for the design of novel FXR ligands in treating autoimmune disorders, but also uncover a novel therapeutic effect for vidofludimus on NAFLD based on the newly established relationships among drugs, targets, and diseases.

The Selective Oral Immunomodulator Vidofludimus in Patients with Active Rheumatoid Arthritis: Safety Results from the COMPONENT Study

INTRODUCTION

The dihydroorotate dehydrogenase (DHODH) inhibitors leflunomide and teriflunomide are immunomodulatory agents approved to treat rheumatoid arthritis (RA) and multiple sclerosis, respectively, and are actively being investigated as therapeutic agents for other immune-related diseases; however, both structurally related compounds have a number of potentially serious adverse effects. Vidofludimus, a new selective second-generation DHODH inhibitor, is chemically distinct from leflunomide/teriflunomide and appears to exhibit a distinct safety profile.

OBJECTIVE

The aim of the COMPONENT study was to assess the efficacy, safety, and pharmacokinetics of vidofludimus in the treatment of patients with active RA on a background therapy of methotrexate. This report focuses solely on the safety results of the COMPONENT trial.

METHODS

Patients received once-daily oral vidofludimus (N = 122) or placebo (N = 119) along with their standard of care methotrexate treatment for 13 weeks. Efficacy endpoints were assessed. Safety parameters were monitored throughout treatment and at follow-up. Plasma concentrations of vidofludimus were measured.

RESULTS

The primary efficacy endpoint, American College of Rheumatology 20 (ACR₂₀) responder rate at 13 weeks, demonstrated numerical superiority in the treatment group compared with placebo; however, it did not reach statistical significance. Nonetheless, the COMPONENT study yielded important safety and pharmacokinetic data that could provide important information regarding the use of vidofludimus in other clinical trials, not only for RA but also for other autoimmune diseases. A safety profile for vidofludimus similar to placebo was obtained in this RA patient population. This includes similar rates of the adverse events of diarrhea, alopecia, neutropenia, and elevated liver enzymes, all of which are known drug-related adverse events reported for leflunomide and teriflunomide. A potential pharmacokinetic interaction between vidofludimus and methotrexate was observed.

CONCLUSIONS

Vidofludimus demonstrated a positive safety profile, making it a promising candidate for the treatment of a variety of immune-related diseases.

TRIAL REGISTRATIONS

ClinicalTrials.gov identifier: NCT01010581.

Dysregulation of de novo nucleotide biosynthetic pathway enzymes in cancer and targeting opportunities

Cancer is a disease of uncontrolled cell growth and a major cause of death worldwide. Many molecular events characterize tumor initiation and progression. Global gene expression analyses using next-generation sequencing, proteomics and metabolomics show genomic, epigenetic, and metabolite concentration changes in various tumors. Molecular alterations identified include multiple cancer-driving mutations, gene fusions, amplifications, deletions, and post-translational modifications. Data integration from many high-throughput platforms unraveled dysregulation in many metabolic pathways in cancer. Since cancer cells are fast-growing, their metabolic needs are enhanced, hence the requirement for de novo synthesis of essential metabolites. One critical requirement of fast-growing cells and a historically important pathway in cancer is the nucleotide biosynthetic pathway and its enzymes are valuable targets for small molecule inhibition. Purines and pyrimidines are building blocks of DNA synthesis and due to their excessive growth, cancer cells extensively utilize de novo pathways for nucleotide biosynthesis. Methotrexate, one of the early chemotherapeutic agents, targets dihydrofolate reductase of the folate metabolic pathway that is involved in nucleotide biosynthesis. In this review, we discuss the nucleotide biosynthetic pathways in cancer and targeting opportunities.

VPR-254: an inhibitor of ROR-gamma T with potential utility for the treatment of inflammatory bowel disease

INTRODUCTION

Retinoic Acid Related Orphan Nuclear Receptor gamma T (RORγT) is a lineage specifying transcription factor for IL-17 expressing cells, which may contribute to the pathogenesis of Inflammatory Bowel Disease (IBD). VPR-254 is a selective in vitro inhibitor of RORγT.

AIMS

The main goals of our study were twofold: (1) To determine if ex vivo treatment with VPR-254 reduced relevant cytokine (IL-17 and IL-21) secretion from colonic strips of mice with colitis; (2) To determine if treatment of mice with VPR-254 attenuated parameters of colitis, using three murine IBD models.

METHODS

VPR-254 was evaluated ex vivo in a colonic strip assay, using tissue from mice with Dextran sulfate sodium (DSS)-induced colitis. In vivo, VPR-254 was evaluated for efficacy in DSS, Trintirobenzenesulfonic acid (TNBS) and Anti-CD40 antibody-induced murine models of colitis.

RESULTS

VPR-254 reduced the production of key pro-inflammatory cytokines (e.g., IL-17) in ex vivo and in vivo models of colitis. This small molecule inhibitor of RORγT also improved various morphometric and histological parameters associated with three diverse murine models of IBD.

CONCLUSION

Our results support the concept that an inhibitor of ROR-gamma T may have potential utility for the treatment of IBD.

Structural Optimization and Structure-Activity Relationship of 4-Thiazolidinone Derivatives as Novel Inhibitors of Human Dihydroorotate Dehydrogenase

Human dihydroorotate dehydrogenase (hDHODH), one of the attractive targets for the development of immunosuppressive drugs, is also a potential target of anticancer drugs and anti-leukemic drugs. The development of promising hDHODH inhibitors is in high demand. Based on the unique binding mode of our previous reported 4-thiazolidinone derivatives, via molecular docking method, three new series 4-thiazolidinone derivatives were designed and synthesized as hDHODH inhibitors. The preliminary structure–activity relationship was investigated. Compound 9 of biphenyl series and compound 37 of amide series displayed IC₅₀ values of 1.32 μM and 1.45 μM, respectively. This research will provide valuable reference for the research of new structures of hDHODH inhibitors.

Immunomodulatory effects of probiotics: Can they be used to treat allergies and autoimmune diseases?

As a person ages, physiological, immunological and gut microbiome changes collectively result in an array of chronic conditions. According to the 'hygiene hypothesis' the increasing prevalence of immune-mediated disorders may be related to intestinal dysbiosis, leading to immune dysfunction and associated conditions such as eczema, asthma, allergies and autoimmune diseases. Beneficial probiotic bacteria can be utilized by increasing their abundance within the gastrointestinal lumen, which in turn will modulate immune cells, such as, T helper (Th)-1, Th2, Th17, regulatory T (Treg) cells and B cells, which have direct relevance to human health and the pathogenesis of immune disorders. Here, we describe the cross-talk between probiotics and the gastrointestinal immune system, and their effects in relation to inflammatory bowel disease, multiple sclerosis, allergies and atopic dermatitis.

Targeting of Hematologic Malignancies with PTC299, A Novel Potent Inhibitor of Dihydroorotate Dehydrogenase with Favorable Pharmaceutical Properties

PTC299 was identified as an inhibitor of VEGFA mRNA translation in a phenotypic screen and evaluated in the clinic for treatment of solid tumors. To guide precision cancer treatment, we performed extensive biological characterization of the activity of PTC299 and demonstrated that inhibition of VEGF production and cell proliferation by PTC299 is linked to a decrease in uridine nucleotides by targeting dihydroorotate dehydrogenase (DHODH), a rate-limiting enzyme for de novo pyrimidine nucleotide synthesis. Unlike previously reported DHODH inhibitors that were identified using in vitro enzyme assays, PTC299 is a more potent inhibitor of DHODH in isolated mitochondria suggesting that mitochondrial membrane lipid engagement in the DHODH conformation in situ is required for its optimal activity. PTC299 has broad and potent activity against hematologic cancer cells in preclinical models, reflecting a reduced pyrimidine nucleotide salvage pathway in leukemia cells. Archived serum samples from patients treated with PTC299 demonstrated increased levels of dihydroorotate, the substrate of DHODH, indicating target engagement in patients. PTC299 has advantages over previously reported DHODH inhibitors, including greater potency, good oral bioavailability, and lack of off-target kinase inhibition and myelosuppression, and thus may be useful for the targeted treatment of hematologic malignancies.

Anti-mouse CD52 Treatment Ameliorates Colitis through Suppressing Th1/17 Mediated Inflammation and Promoting Tregs Differentiation in IL-10 Deficient Mice

Recent studies suggested that excessive T helper (Th)1/17 cells concomitant with regulatory T cell deficiency might play important roles in Crohn's disease. Anti-cluster of differentiation 52 (CD52) monoclonal antibody (mAb), which aims on CD52 antigen on mature immunocytes, has both T cell depletion and immunosuppressive activities. In this study, we evaluated the therapeutic effects and possible mechanisms of anti-CD52 treatment on interleukin-10 (IL-10) deficient mouse. Anti-mouse CD52 mAb was administered to C3H/HeJBir.IL-10^-/- (C3H.IL-10^-/-) mice intraperitoneally 20 µg per week for 2 weeks. The disease activity index, body weight, the histological grading of colitis, and levels of tumor necrosis factor (TNF)-α, interferon (IFN)-γ, IL-17 and IL-6 in colon were quantified after treatment. In addition, CD25, Forkhead box P3 (Foxp3) and transforming growth factor (TGF)-β gene as well as the percentage of CD25⁺Foxp3⁺ T cells in colon were also measured. The severity of colitis in IL-10^-/- mice was significantly decreased by the treatment, with improvement of colon histological grade. The treatment also decreased the TNF-α, IFN-γ, IL-17 and IL-6 levels in colon. Furthermore, the treatment up-regulated the mRNA expression of CD25, Foxp3 and TGF-β gene as well as the percentage of CD25⁺Foxp3⁺ T cells in colon lamina propria mononuclear cells (LPMCs) of IL-10^-/- mice. Our data might indicate that anti-CD52 treatment could ameliorate the colitis of C3H.IL-10^-/- mice and it might be related to the suppression of Th1/17 related inflammation and the promotion of regulatory T cell differentiation. Thus, our data reveals that anti-CD52 treatment may hold potential for clinical applications for Crohn's disease treatment.

Immunological pathogenesis of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic inflammatory state of the gastrointestinal tract and can be classified into 2 main clinical phenomena: Crohn's disease (CD) and ulcerative colitis (UC). The pathogenesis of IBD, including CD and UC, involves the presence of pathogenic factors such as abnormal gut microbiota, immune response dysregulation, environmental changes, and gene variants. Although many investigations have tried to identify novel pathogenic factors associated with IBD that are related to environmental, genetic, microbial, and immune response factors, a full understanding of IBD pathogenesis is unclear. Thus, IBD treatment is far from optimal, and patient outcomes can be unsatisfactory. As result of massive studying on IBD, T helper 17 (Th17) cells and innate lymphoid cells (ILCs) are investigated on their effects on IBD. A recent study of the plasticity of Th17 cells focused primarily on colitis. ILCs also emerging as novel cell family, which play a role in the pathogenesis of IBD. IBD immunopathogenesis is key to understanding the causes of IBD and can lead to the development of IBD therapies. The aim of this review is to explain the pathogenesis of IBD, with a focus on immunological factors and therapies.

Gleaning Insights from Fecal Microbiota Transplantation and Probiotic Studies for the Rational Design of Combination Microbial Therapies

Beneficial microorganisms hold promise for the treatment of numerous gastrointestinal diseases. The transfer of whole microbiota via fecal transplantation has already been shown to ameliorate the severity of diseases such as Clostridium difficile infection, inflammatory bowel disease, and others. However, the exact mechanisms of fecal microbiota transplant efficacy and the particular strains conferring this benefit are still unclear. Rationally designed combinations of microbial preparations may enable more efficient and effective treatment approaches tailored to particular diseases. Here we use an infectious disease, C. difficile infection, and an inflammatory disorder, the inflammatory bowel disease ulcerative colitis, as examples to facilitate the discussion of how microbial therapy might be rationally designed for specific gastrointestinal diseases. Fecal microbiota transplantation has already shown some efficacy in the treatment of both these disorders; detailed comparisons of studies evaluating commensal and probiotic organisms in the context of these disparate gastrointestinal diseases may shed light on potential protective mechanisms and elucidate how future microbial therapies can be tailored to particular diseases.

Th17 Cells as Potential Probiotic Therapeutic Targets in Inflammatory Bowel Diseases

Inflammatory bowel diseases (IBD) are characterized by wasting and chronic intestinal inflammation triggered by various cytokine-mediated pathways. In recent years, it was shown that T helper 17 (Th17) cells are involved in the pathogenesis of IBD, which makes them an attractive therapeutic target. Th17 cells preferentially produce interleukin (IL)-17A–F as signature cytokines. The role of the interplay between host genetics and intestinal microbiota in the pathogenesis of IBD was demonstrated. Probiotics are live microorganisms that when orally ingested in adequate amounts, confer a health benefit to the host by modulating the enteric flora or by stimulating the local immune system. Several studies indicated the effectiveness of probiotics in preventing and treating IBD (ulcerative colitis, and Crohn’s disease). Furthermore, there is mounting evidence of probiotics selectively targeting the Th17 lineage in the prevention and management of inflammatory and autoimmune diseases such as IBD. This review highlights critical roles of Th17 cells in the pathogenesis of IBD and the rationale for using probiotics as a novel therapeutic approach for IBD through manipulation of Th17 cells. The potential molecular mechanisms by which probiotics modulate Th17 cells differentiation and production are also discussed.

Lactobacillus acidophilus suppresses colitis-associated activation of the IL-23/Th17 axis

The aim of this paper is to determine the modulatory effects of Lactobacillus acidophilus on the IL-23/Th17 immune axis in experimental colitis. DSS-induced mouse models of UC were to be saline, hormones, and different concentrations of Lactobacillus acidophilus intervention. The expression of interleukin- (IL-) 17, tumor necrosis factor α (TNFα), IL-23, transforming growth factor β1 (TGFβ1), signal transducer and activator of transcription 3 (STAT3), and phosphorylated (p)-STAT3 was examined by RT-PCR, Western blotting, and immunohistochemical analysis. And the results showed that administration of L. acidophilus suppressed Th17 cell-mediated secretion of proinflammatory cytokine IL-17 through downregulation of IL-23 and TGFβ1 expression and downstream phosphorylation of p-STAT3.

The synthetic triterpenoid (CDDO-Im) inhibits STAT3, as well as IL-17, and improves DSS-induced colitis in mice

INTRODUCTION

Synthetic triterpenoids inhibit IL-17 and improve autoimmune disease in mice. A prototype triterpenoid, 1-[2-cyano-3-,12-dioxooleana-1,9(11)-dien-28-oyl] imidazole (CDDO-Im), also inhibits signal transducer and activator of transcription 3 (STAT3) activation.

AIMS

The goals of our study were twofold: (1) To determine if ex vivo treatment with CDDO-Im attenuated colonic IL-17 secretion from isolated splenocytes and colonic strips; (2) To determine if oral treatment with CDDO-Im improved DSS-induced colitis in mice.

METHODS

Splenocytes were isolated from male Balb/c mice. Colitis was induced in rodents, with either trinitrobenzene sulfonic acid or dextran sulfate sodium (DSS). Colonic strips were collected 5 or 6 days after colitis induction. Splenocytes or colonic strips were exposed to CDDO-Im (0.5-2 μM) concomitantly with IL-23 + IL-1β. Supernatants were collected after 48 or 24 h, and IL-17 was measured by ELISA. Using a DSS colitis model, mice were dosed orally with vehicle or CDDO-Im (20 mg/kg) over a 5-day period. Subsequently, various parameters of colitis were determined on study day 6.

RESULTS

Ex vivo treatment with CDDO-Im inhibited IL-17 secretion from splenocytes and colonic strips. The IC50 values were ≤0.62 μM. In vivo, CDDO-Im improved the altered colonic histology, and cytokine (IL-6, and IL-17) contents. Colonic STAT3 activation was also significantly reduced by CDDO-Im treatment. CDDO-Im attenuated IL-17 secretion in ex vivo models of inflammation. In vivo, histological and biochemical parameters of colitis were improved in CDDO-Im treated mice.

CONCLUSION

CDDO-Im has a unique pharmacological profile, which supports further testing in animal models of IBD.

Role of Th17 Cells in the Pathogenesis of Human IBD

The gastrointestinal tract plays a central role in immune system, being able to mount efficient immune responses against pathogens, keeping the homeostasis of the human gut. However, conditions like Crohn's disease (CD) or ulcerative colitis (UC), the main forms of inflammatory bowel diseases (IBD), are related to an excessive and uncontrolled immune response against normal microbiota, through the activation of CD4(+) T helper (Th) cells. Classically, IBD was thought to be primarily mediated by Th1 cells in CD or Th2 cells in UC, but it is now known that Th17 cells and their related cytokines are crucial mediators in both conditions. Th17 cells massively infiltrate the inflamed intestine of IBD patients, where they produce interleukin- (IL-) 17A and other cytokines, triggering and amplifying the inflammatory process. However, these cells show functional plasticity, and they can be converted into either IFN- γ producing Th1 cells or regulatory T cells. This review will summarize the current knowledge regarding the regulation and functional role of Th17 cells in the gut. Deeper insights into their plasticity in inflammatory conditions will contribute to advancing our understanding of the mechanisms that regulate mucosal homeostasis and inflammation in the gut, promoting the design of novel therapeutic approaches for IBD.

Inhibition of IL-17 as a pharmacological approach for IBD

Several experimental approaches have been utilized, in order to critically examine the roles of IL-17 family members in intestinal inflammation. These approaches have included: (1) the use of IL-17A and IL-17F-deficient mice, (2) specific antibodies directed against IL-17, (3) an IL-17 vaccine, (4) methods to block the IL-17 receptor and (5) small-molecule inhibitors of IL-17. Previous studies found somewhat conflicting results in preclinical models of Inflammatory Bowel Disease (IBD), using specific strains of IL-17-deficient mice. This paper will review the preclinical results using various pharmacological approaches [specific IL-17 antibodies, an IL-17 receptor fusion protein, IL-12/IL-23 p40 subunit and IL-17 vaccine approaches, as well as a small molecule inhibitor (Vidofludimus)] to inhibit IL-17 in animal models of IBD. Recent clinical results in patients with IBD will also be discussed for Secukinumab (an IL-17A antibody), Brodalumab (an IL-17 receptor antibody) and two small-molecule drugs (Vidofludimus and Tofacitinib), which inhibit IL-17 as part of their overall pharmacological profiles. This review paper will also discuss some pharmacological lessons learned from the preclinical and clinical studies with anti-IL-17 drugs, as related to drug pharmacodynamics, IL-17 receptor subtypes and other pertinent factors. Finally, future pharmacological approaches of interest will be discussed, such as: (1) Retinoic acid receptor-related orphan nuclear receptor gamma t (Rorγt) antagonists, (2) Retinoic acid receptor alpha (RARα) antagonists, (3) Pim-1 kinase inhibitors and (4) Dual small-molecule inhibitors of NF-κB and STAT3, like synthetic triterpenoids.

Investigational cytokine-targeted therapies for ulcerative colitis

INTRODUCTION

Up to one-third of patients with ulcerative colitis (UC) do not respond to standard medications, including mesalamine, steroids and thiopurines. The recognition that UC-related pathological process is the result of an altered balance between inflammatory and counter-regulatory signals, mostly mediated by cytokines, has led to the development of novel compounds, which are now ready to move into clinical practice. This article summarizes the recent data on the development and use of compounds either inhibiting inflammatory cytokines or enhancing the activity of counter-regulatory cytokines in patients with UC and murine models of UC.

AREAS COVERED

A PubMed search was performed using the following keywords: 'ulcerative colitis', 'therapy', 'treatment' and 'cytokine'. In addition, ongoing clinical trials were checked and compounds were searched on the website of pharmaceutical companies.

EXPERT OPINION

Several investigational cytokine-based therapies have provided promising results in attenuating clinical activity in patients with UC and mice with experimental colitis. However, clinical and immunological heterogeneity of UC patients, therapy-related side effects and redundant biological functions of cytokines represent potential pitfalls and should be considered in optimizing therapeutic strategies.

On dihydroorotate dehydrogenases and their inhibitors and uses

Proper nucleosides availability is crucial for the proliferation of living entities (eukaryotic cells, parasites, bacteria, and virus). Accordingly, the uses of inhibitors of the de novo nucleosides biosynthetic pathways have been investigated in the past. In the following we have focused on dihydroorotate dehydrogenase (DHODH), the fourth enzyme in the de novo pyrimidine nucleosides biosynthetic pathway. We first described the different types of enzyme in terms of sequence, structure, and biochemistry, including the reported bioassays. In a second part, the series of inhibitors of this enzyme along with a description of their potential or actual uses were reviewed. These inhibitors are indeed used in medicine to treat autoimmune diseases such as rheumatoid arthritis or multiple sclerosis (leflunomide and teriflunomide) and have been investigated in treatments of cancer, virus, and parasite infections (i.e., malaria) as well as in crop science.