Design, synthesis and biological evaluation of 7 H -pyrrolo[2,3- d ]pyrimidin-4-amine derivatives as selective Btk inhibitors with improved pharmacokinetic properties for the treatment of rheumatoid arthritis

Design and synthesis of highly selective Janus kinase 3 covalent inhibitors for the treatment of rheumatoid arthritis

Selective inhibition of Janus kinase 3 (JAK3) is a promising strategy for the treatment of autoimmune diseases. Based on the discovery of a hydrophobic pocket unutilized between the lead compound RB1 and the JAK3 protein, a series of covalent JAK3 inhibitors were prepared by introducing various aromatic fragments to RB1. Among them, J1b (JAK3 IC50 = 7.2 nM, other JAKs IC50 > 1000 nM) stood out because of its low toxicity (MTD > 2 g/kg) and superior anti-inflammatory activity in Institute of Cancer Research mice. Moreover, the acceptable bioavailability (F% = 31.69%) ensured that J1b displayed excellent immune regulation in collagen-induced arthritis mice, whose joints in the high-dose group were almost recovered to a normal state. Given its clear kinase selectivity (Bmx IC50 = 539.9 nM, other Cys909 kinases IC50 > 1000 nM), J1b was nominated as a highly selective JAK3 covalent inhibitor, which could be used to safely treat arthritis and other autoimmune diseases.

Ibrutinib Delays ALS Installation and Increases Survival of SOD1G93A Mice by Modulating PI3K/mTOR/Akt Signaling

Amyotrophic lateral sclerosis (ALS) is a fatal multisystem degenerative disorder with minimal available therapeutic. However, some recent studies showed promising results of immunological-based treatment. Here, we aimed to evaluate the efficacy of ibrutinib against ALS-associated abnormalities by targeting inflammation and muscular atrophy. Ibrutinib was administrated orally to SOD1 G93A mice from 6 to 19 weeks for prophylactic administration and 13 to 19 weeks for therapeutic administration. Our results demonstrated that ibrutinib treatment significantly delayed ALS-like symptom onset in the SOD1 G93A mice, as shown by improved survival time and reduced behavioral impairments. Ibrutinib treatment significantly reduced muscular atrophy by increasing muscle/body weight and decreasing muscular necrosis. The ibrutinib treatment also considerably reduced pro-inflammatory cytokine production, IBA-1, and GFAP expression, possibly mediated by mTOR/Akt/Pi3k signaling in the medulla, motor cortex and spinal cord of the ALS mice. In conclusion, our study demonstrated that ibrutinib could delay ALS onset, increase survival time, and reduce ALS progression by targeting inflammation and muscular atrophy via mTOR/Akt/PI3K modulation.

A study on the antibacterial activity and antimicrobial resistance of pyridinium cationic pillar[5]arene against Staphylococcus aureus and Escherichia coli

An increasing number of infections caused by multidrug-resistant (MDR) Staphylococcus aureus （S. aureus） and Escherichia coli （E. coli） have severely affected human society. Thus, it is essential to develop an alternative type of antibacterial agents that has a different bacterial resistance mechanism from that of traditional antibiotics. After the synthesis and structural characterization of a cationic pillar[5]arene with pyridinium groups (PP5), the antibacterial and antibiofilm activities as well as its microbial resistance were systematically investigated. In-depth evaluation of biological studies revealed that PP5 was an active antibacterial agent, with surprising antibiofilm formation ability against E. coli and S. aureus. From the results of differential scanning calorimetry and transmission electron microscopy, it was concluded that the microbicidal activity of PP5 was due to the physical disruption of the pathogen's membrane and the subsequent leakage of cytoplasmic components, which could greatly reduce the rapid generation of resistance. It was presented that the easily available PP5 has high activity to inhibit Gram-positive and Gram-negative bacteria and/or their biofilms with low cytotoxicity. This pillar[5]arene derivative can be used as a good candidate for controlling drug-resistant pathogenic bacterial infections and treating MDR bacteria.

Exploration of 4-aminopyrrolo[2,3-d]pyrimidine as antitubercular agents

Tuberculosis (TB) is one of the leading causes of death worldwide. Developing new anti-TB compounds using cost-effective processes is critical to reduce TB incidence and accomplish the End TB Strategy milestone. Herein, we describe the synthesis and structure–activity relationships of a library of thirty 7H-Pyrrolo[2,3-d]pyrimidine derivatives providing insights into the contributions of different aromatic, aryl and alkyl substitution at the C-4 position of the 7-deazapurine ring. The minimum inhibitory concentration (MIC) of the compounds against the green fluorescent protein (GFP) reporter strain of Mycobacterium tuberculosis was assayed using the standard broth microdilution method, and cell toxicity was determined using the MTT assay. Sixteen compounds displayed in vitro activity against the GFP reporter strain of Mycobacterium tuberculosis with MIC₉₀ values of 0.488–62.5 µM. This study highlights the most potent derivative, N-(4-phenoxy phenyl)-7H-pyrrolo[2,3-d]pyrimidin-4-amine with a MIC₉₀ value of 0.488 µM and was non-cytotoxic to the Vero cell line. Moreover, all the potent compounds from this series have a ClogP value less than 4 and molecular weight < 400; thus, likely to maintain drug-likeness during lead optimisation.

Some important inhibitors and mechanisms of rheumatoid arthritis

Rheumatoid arthritis is a chronic disease that seriously affects human health and quality of life, and it is one of the main causes of labor loss and disability. Many countries have listed rheumatoid arthritis as one of the national a key diseases to tackle. The pathogenesis of RA in humans is still unknown, and medical researchers believe that the pathogenesis of RA may be the result of a combination of genetic and environmental factors. RA is an incurable condition that can only be controlled and treated with conventional drugs. In this paper, the pathologic features and pathogenesis of RA were introduced, and the research progress of new anti-rheumatoid arthritis chemical drugs in recent years was reviewed.

The Development of BTK Inhibitors: A Five-Year Update

Bruton's tyrosine kinase (BTK) represented, in the past ten years, an important target for the development of new therapeutic agents that could be useful for cancer and autoimmune disorders. To date, five compounds, able to block BTK in an irreversible manner, have been launched in the market, whereas many reversible BTK inhibitors (BTKIs), with reduced side effects that are more useful for long-term administration in autoimmune disorders, are under clinical investigation. Despite the presence in the literature of many articles and reviews, studies on BTK function and BTKIs are of great interest for pharmaceutical companies as well as academia. This review is focused on compounds that have appeared in the literature from 2017 that are able to block BTK in an irreversible or reversible manner; also, new promising tunable irreversible inhibitors, as well as PROTAC molecules, have been reported. This summary could improve the knowledge of the chemical diversity of BTKIs and provide information for future studies, particularly from the medicinal chemistry point of view. Data reported here are collected from different databases (Scifinder, Web of Science, Scopus, Google Scholar, and Pubmed) using "BTK" and "BTK inhibitors" as keywords.

CORAL: Monte Carlo based global QSAR modelling of Bruton tyrosine kinase inhibitors using hybrid descriptors

Global QSAR modelling was performed to predict the pIC₅₀ values of 233 diverse heterocyclic compounds as BTK inhibitors with the Monte Carlo algorithm of CORAL software using the DCW hybrid descriptors extracted from SMILES notations of molecules. The dataset of 233 BTK inhibitors was randomly split into training, invisible training, calibration and validation sets. The index of ideality of correlation was also applied to build and judge the predictability of the QSAR models. Eight global QSAR models based on the hybrid optimal descriptor using two target functions, i.e. TF₁ (W_IIC = 0) and TF₂ (W_IIC = 0.2) have been constructed. The statistical parameters of QSAR models computed by TF₂ are more reliable and robust and were used to predict the pIC₅₀ values. The model constructed for split 4 via TF₂ is regarded as the best model and the numerical values of r²_Train, r²_Valid, Q²_Train and Q²_Valid are equal to 0.7981, 0.7429, 0.7898 and 0.6784, respectively. By internal and external validation techniques, the predictability and reliability of the designed models have been assessed. The structural attributes responsible for the increase and decrease of pIC₅₀ of BTK inhibitors were also identified.

Recent Advances in BTK Inhibitors for the Treatment of Inflammatory and Autoimmune Diseases

Bruton’s tyrosine kinase (BTK) plays a crucial role in B-cell receptor and Fc receptor signaling pathways. BTK is also involved in the regulation of Toll-like receptors and chemokine receptors. Given the central role of BTK in immunity, BTK inhibition represents a promising therapeutic approach for the treatment of inflammatory and autoimmune diseases. Great efforts have been made in developing BTK inhibitors for potential clinical applications in inflammatory and autoimmune diseases. This review covers the recent development of BTK inhibitors at preclinical and clinical stages in treating these diseases. Individual examples of three types of inhibitors, namely covalent irreversible inhibitors, covalent reversible inhibitors, and non-covalent reversible inhibitors, are discussed with a focus on their structure, bioactivity and selectivity. Contrary to expectations, reversible BTK inhibitors have not yielded a significant breakthrough so far. The development of covalent, irreversible BTK inhibitors has progressed more rapidly. Many candidates entered different stages of clinical trials; tolebrutinib and evobrutinib are undergoing phase 3 clinical evaluation. Rilzabrutinib, a covalent reversible BTK inhibitor, is now in phase 3 clinical trials and also offers a promising future. An analysis of the protein–inhibitor interactions based on published co-crystal structures provides useful clues for the rational design of safe and effective small-molecule BTK inhibitors.

Emerging small-molecule inhibitors of the Bruton's tyrosine kinase (BTK): Current development

Therapy based on Bruton's tyrosine kinase (BTK) inhibitors one of the major treatment options currently recommended for lymphoma patients. The first generation of BTK inhibitor, Ibrutinib, achieved remarkable progress in the treatment of B-cell malignancies, but still has problems with drug-resistance or off-target induced serious side effects. Therefore, numerous new BTK inhibitors were developed to address this unmet medical need. In parallel, the effect of BTK inhibitors against immune-related diseases has been evaluated in clinical trials. This review summarizes recent progress in the research and development of BTK inhibitors, with a focus on structural characteristics and structure-activity relationships. The structure-refinement process of representative pharmacophores as well as their effects on binding affinity, biological activity and pharmacokinetics profiles were analyzed. The advantages and disadvantages of reversible/irreversible BTK inhibitors and their potential implications were discussed to provide a reference for the rational design and development of novel potent BTK inhibitors.

Anti-inflammatory Ellagitannins from Cleidion brevipetiolatum for the Treatment of Rheumatoid Arthritis

Six new ellagitannins, brevipetins B-G (5 and 7-11), and a new phenolic glucoside, brevipetin A (4), along with six known compounds were isolated from the traditional Chinese medicinal plant Cleidion brevipetiolatum. Their structures and absolute configurations were determined by spectroscopic analyses, chemical methods, and TD-DFT-ECD calculations. Compounds 5-11 exhibited NO inhibitory effects with IC₅₀ values of 1.9-8.2 μM, and 9 showed the most potent inhibitory effect (IC₅₀: 1.9 μM). An in vivo anti-inflammatory assessment of 9 showed that it exerts therapeutic effects in both the carrageenan-induced rat paw edema and collagen-induced arthritis (CIA) models at 50 mg/kg oral administration. The enhanced protein and mRNA expression levels of iNOS (inducible nitric oxide synthase) and COX-2 (cyclooxygenase-2) in LPS-stimulated RAW 264.7 cells were dose-dependently suppressed by 9. An anti-inflammatory mechanistic study revealed that 9 suppressed NF-κB activity by inhibiting IκBα phosphorylation and blocking translocation of p65 from the cytosol to the nucleus. Therefore, 9 might have the potential to be developed as a lead compound for relieving rheumatoid arthritis.

Ibrutinib suppresses LPS-induced neuroinflammatory responses in BV2 microglial cells and wild-type mice

Background

The FDA-approved small-molecule drug ibrutinib is an effective targeted therapy for patients with chronic lymphocytic leukemia (CLL). Ibrutinib inhibits Bruton’s tyrosine kinase (BTK), a kinase involved in B cell receptor signaling. However, the potential regulation of neuroinflammatory responses in the brain by ibrutinib has not been comprehensively examined.

Methods

BV2 microglial cells were treated with ibrutinib (1 μM) or vehicle (1% DMSO), followed by lipopolysaccharide (LPS; 1 μg/ml) or PBS. RT-PCR, immunocytochemistry, and subcellular fractionation were performed to examine the effects of ibrutinib on neuroinflammatory responses. In addition, wild-type mice were sequentially injected with ibrutinib (10 mg/kg, i.p.) or vehicle (10% DMSO, i.p.), followed by LPS (10 mg/kg, i.p.) or PBS, and microglial and astrocyte activations were assessed using immunohistochemistry.

Results

Ibrutinib significantly reduced LPS-induced increases in proinflammatory cytokine levels in BV2 microglial and primary microglial cells but not in primary astrocytes. Ibrutinib regulated TLR4 signaling to alter LPS-induced proinflammatory cytokine levels. In addition, ibrutinib significantly decreased LPS-induced increases in p-AKT and p-STAT3 levels, suggesting that ibrutinib attenuates LPS-induced neuroinflammatory responses by inhibiting AKT/STAT3 signaling pathways. Interestingly, ibrutinib also reduced LPS-induced BV2 microglial cell migration by inhibiting AKT signaling. Moreover, ibrutinib-injected wild-type mice exhibited significantly reduced microglial/astrocyte activation and COX-2 and IL-1β proinflammatory cytokine levels.

Conclusions

Our data provide insights on the mechanisms of a potential therapeutic strategy for neuroinflammation-related diseases.

Electronic supplementary material

The online version of this article (10.1186/s12974-018-1308-0) contains supplementary material, which is available to authorized users.