Treatment of inflammatory dermatoses by tumour necrosis factor antagonists

Bioactive Bibenzyl Enantiomers From the Tubers of Bletilla striata

Six new bibenzyls (three pairs of enantiomers), bletstrins D-F (1-3), were isolated from the ethyl acetate-soluble (EtOAc) extract of tubers of Bletilla striata (Thunb.) Rchb f. Their structures, including absolute configurations, were determined by 1D/2D NMR spectroscopy, optical rotation value, and experimental electronic circular dichroism (ECD) data analyses, respectively. Compounds 1-3 possess a hydroxyl-substituted chiral center on the aliphatic bibenzyl bridge, which represented the first examples of natural bibenzyl enantiomers from the genus of Bletilla. The antibacterial, antitumor necrosis factor (anti-TNF-α), and neuroprotective effects of the isolates have been evaluated. Compounds 3a and 3b were effective against three Gram-positive bacteria with minimum inhibitory concentrations (MICs) of 52-105 μg/ml. Compounds 2a and 2b exhibited significant inhibitory effects on TNF-α-mediated cytotoxicity in L929 cells with IC₅₀ values of 25.7 ± 2.3 μM and 21.7 ± 1.7 μM, respectively. Subsequently, the possible anti-TNF-α mechanism of 2 was investigated by molecular docking simulation. Furthermore, the neuroprotective activities were tested on the H₂O₂-induced PC12 cell injury model, and compounds 2b, 3a, and 3b (10 μM) could obviously protect the cells with the cell viabilities of 57.86 ± 2.08%, 64.82 ± 2.84%, and 64.11 ± 2.52%, respectively.

Ligand-based pharmacophore modeling of TNF-α to design novel inhibitors using virtual screening and molecular dynamics

Tumor necrosis factor-α (TNF-α) is one of the promising targets for treating inflammatory (Crohn disease, psoriasis, psoriatic arthritis, rheumatoid arthritis) and various other diseases. Commercially available TNF-α inhibitors are associated with several risks and limitations. In the present study, we have identified small TNF-α inhibitors using in silico approaches, namely pharmacophore modeling, virtual screening, molecular docking, molecular dynamics simulation and free binding energy calculations. The study yielded better and potent hits that bind to TNF-α with significant affinity. The best pharmacophore model generated using LigandScout has an efficient hit rate and Area Under the operating Curve. High throughput virtual screening of SPECS database molecules against crystal structure of TNF-α protein, coupled with physicochemical filtration, PAINS test. Virtual hit compounds used for molecular docking enabled the identification of 20 compounds with better binding energies when compared with previously known TNF-α inhibitors. MD simulation analysis on 20 virtual identified hits showed that ligand binding with TNF-α protein is stable and protein-ligand conformation remains unchanged. Further, 16 compounds passed ADMET analysis suggesting these identified hit compounds are suitable for designing a future class of potent TNF-α inhibitors.Communicated by Ramaswamy H. Sarma.

Structural insight into TNF-α inhibitors through combining pharmacophore-based virtual screening and molecular dynamic simulation

Tumor Necrosis Factor-alpha (TNF-α), a multifunctional cytokine responsible for providing resistance against infections, inflammation, and cancers. TNF-α has emerged as a promising drug target against several autoimmune and inflammatory disorders. Several synthetic antibodies (Infliximab, Etanercept, and Adalimumab) are available, but their potential to cause severe side effects has prompted them to develop alternative small molecules-based therapies for inhibition of TNF-α. In the present study, combined in silico approaches based on pharmacophore modeling, virtual screening, molecular docking, and molecular dynamics studies were employed to understand significant direct interactions between TNF-α protein and small molecule inhibitors. Initially, four different small molecule libraries (∼17.5 million molecules) were virtually screened against the selected pharmacophore model. The identified hits were further subjected to molecular docking studies. The three potent lead compounds (ZINC05848961, ZINC09402309, ZINC04502991) were further subjected to 100 ns molecular dynamic studies to examine their stability. Our docking and molecular dynamic analysis revealed that the selected lead compounds target the TNF receptor (TNFR) and efficiently block the production of TNF. Moreover, in silico ADMET (Absorption, Distribution, Metabolism, Excretion and Toxicity) analysis revealed that all the predicted compounds have good pharmacokinetic properties with high gastrointestinal absorption and a decent bioavailability score. Furthermore, toxicity profiles further evidenced that these compounds have no risk of being mutagenic, tumorigenic, reproductive and irritant except ZINC11915498. In conclusion, the present study could serve as the starting point to develop new therapeutic regimens to treat various TNF- related diseases. Communicated by Ramaswamy H. Sarma.

Design, Synthesis, and Evaluation of Dihydrobenzo[cd]indole-6-sulfonamide as TNF-α Inhibitors

Tumor necrosis factor-α (TNF-α) plays a pivotal role in inflammatory response. Dysregulation of TNF can lead to a variety of disastrous pathological effects, including auto-inflammatory diseases. Antibodies that directly targeting TNF-α have been proven effective in suppressing symptoms of these disorders. Compared to protein drugs, small molecule drugs are normally orally available and less expensive. Till now, peptide and small molecule TNF-α inhibitors are still in the early stage of development, and much more efforts should be made. In a previously study, we reported a TNF-α inhibitor, EJMC-1 with modest activity. Here, we optimized this compound by shape screen and rational design. In the first round, we screened commercial compound library for EJMC-1 analogs based on shape similarity. Out of the 68 compounds tested, 20 compounds showed better binding affinity than EJMC-1 in the SPR competitive binding assay. These 20 compounds were tested in cell assay and the most potent compound was 2-oxo-N-phenyl-1,2-dihydrobenzo[cd]indole-6-sulfonamide (S10) with an IC₅₀ of 14 μM, which was 2.2-fold stronger than EJMC-1. Based on the docking analysis of S10 and EJMC-1 binding with TNF-α, in the second round, we designed S10 analogs, purchased seven of them, and synthesized seven new compounds. The best compound, 4e showed an IC₅₀-value of 3 μM in cell assay, which was 14-fold stronger than EJMC-1. 4e was among the most potent TNF-α organic compound inhibitors reported so far. Our study demonstrated that 2-oxo-N-phenyl-1,2-dihydrobenzo[cd]indole-6-sulfonamide analogs could be developed as potent TNF-α inhibitors. 4e can be further optimized for its activity and properties. Our study provides insights into designing small molecule inhibitors directly targeting TNF-α and for protein–protein interaction inhibitor design.

De novo design of helical peptides to inhibit tumor necrosis factor-α by disrupting its trimer formation

Helical peptide TNFα inhibitors were designed by targeting their dimer structure.

Discovery of highly potent TNFα inhibitors using virtual screen

Tumor necrosis factor-α (TNFα) is a validated therapeutic target for various autoimmune disorders such as rheumatoid arthritis and asthma. All TNFα inhibitors currently on the market are biologics, making the development of small molecule alternatives in urgent need. However, only a few successful cases of direct TNFα antagonization in vitro have been reported. Here, we present the identification of several small molecule candidates able to effectively reduce TNFα activity in vitro and in cell assays. Virtual screen targeting TNFα dimer was performed on the SPECS database and 101 compounds were selected for experimental testing. Two compounds, 1 and 2, displayed considerable inhibitory activity. Follow-up structure-activity relationship analysis of compound 1 identified 3 molecules with low micromolar cell-level inhibitory activity. Compound 11 showed an IC50 value of 14 μM, making it among the most potent TNFα small molecule inhibitors reported. These compounds provide new scaffolds for future development of small molecule drugs against TNFα.

Roxithromycin downregulates production of CTACK/CCL27 and MIP-3α/CCL20 from epidermal keratinocytes

Cutaneous T cell-attracting chemokine (CTACK)/CCL27 and macrophage inflammatory protein (MIP)-3α/CCL20 are the major inflammatory chemokines involved in skin inflammation. The present study showed that roxithromycin (RXM) suppressed the TNFα-induced production of CCL27 and CCL20 in HaCaT keratinocytes and normal human keratinocytes (NHKs) in a dose-dependent manner. The production of CCL20 induced by TNFα was suppressed by the addition of inhibitors of nuclear factor kappa B (NFκB). RXM suppressed NFκB activity induced by TNFα. RXM, by regulating CCL27 and CCL20, may contribute to the modulation of inflammation.

Biologics: target-specific treatment of systemic and cutaneous autoimmune diseases

Biologics are becoming important in the treatment of systemic and cutaneous autoimmune diseases. They are designed to target specific components of immune system. As the new drugs are capable of targeting proteins in a more specific fashion, yet have lower risks of systemic side-effects, they have considerable advantages over the older immunomodulators. The development of TNF-alpha blockers in the treatment of psoriasis, psoriatic arthritis, rheumatoid arthritis, Crohn's disease and ankylosing spondylitis have been major breakthroughs. Likewise, B-cell depletion has proved to be equally revolutionary for the treatment of lupus, pemphigus, certain vasculitides etc. But all said and done, the development of these molecules and their clinical usage are still at evolving stages. Consensus needs be formed to further categorize the clinical profiles of the patients in whom biologics are to be used in the future, given that the long-term safety profiles of these agents are very much unknown at present.

The Enigmatic Development of Psoriasis and Psoriasiform Lesions During Anti-TNF Therapy: A Review

OBJECTIVES

The paradoxical observation that antitumor necrosis factor (anti-TNF) agents are capable of inducing psoriasis and psoriasiform skin lesions while also being therapy for psoriasis gained substantial support following the description of this condition by several authors. Our aim was to review the literature of this subject.

METHODS

A retrospective review of the literature was performed using the Medline database between 2005 and February 2007.

RESULTS

Since the first publication by our group in April 2005 to the present, 50 cases of this type of dermatitis have been described. More than half of the cases were associated with the use of infliximab. Different presentations of psoriasis were reported, plaque form being the most prevalent. A number of clinical and immunological observations suggest a cytokine disequilibrium in patients receiving chronic anti-TNF therapy leading to this condition. Treatment for the skin disease includes changing the anti-TNF agent or discontinuing the medication.

CONCLUSIONS

The appearance of psoriasis and psoriasiform lesions during chronic anti-TNF therapy is dependent on the presence of known and unknown interrelated factors. Enhanced clinician awareness of this drug complication and further investigation of its mechanisms are warranted.