Kinase inhibitors: A new tool for the treatment of rheumatoid arthritis

Phosphoproteomic profiling of early rheumatoid arthritis synovium reveals active signalling pathways and differentiates inflammatory pathotypes

BACKGROUND

Kinases are intracellular signalling mediators and key to sustaining the inflammatory process in rheumatoid arthritis (RA). Oral inhibitors of Janus Kinase family (JAKs) are widely used in RA, while inhibitors of other kinase families e.g. phosphoinositide 3-kinase (PI3K) are under development. Most current biomarker platforms quantify mRNA/protein levels, but give no direct information on whether proteins are active/inactive. Phosphoproteome analysis has the potential to measure specific enzyme activation status at tissue level.

METHODS

We validated the feasibility of phosphoproteome and total proteome analysis on 8 pre-treatment synovial biopsies from treatment-naive RA patients using label-free mass spectrometry, to identify active cell signalling pathways in synovial tissue which might explain failure to respond to RA therapeutics.

RESULTS

Differential expression analysis and functional enrichment revealed clear separation of phosphoproteome and proteome profiles between lymphoid and myeloid RA pathotypes. Abundance of specific phosphosites was associated with the degree of inflammatory state. The lymphoid pathotype was enriched with lymphoproliferative signalling phosphosites, including Mammalian Target Of Rapamycin (MTOR) signalling, whereas the myeloid pathotype was associated with Mitogen-Activated Protein Kinase (MAPK) and CDK mediated signalling. This analysis also highlighted novel kinases not previously linked to RA, such as Protein Kinase, DNA-Activated, Catalytic Subunit (PRKDC) in the myeloid pathotype. Several phosphosites correlated with clinical features, such as Disease-Activity-Score (DAS)-28, suggesting that phosphosite analysis has potential for identifying novel biomarkers at tissue-level of disease severity and prognosis.

CONCLUSIONS

Specific phosphoproteome/proteome signatures delineate RA pathotypes and may have clinical utility for stratifying patients for personalised medicine in RA.

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.

A Tale of Two Immune Cells in Rheumatoid Arthritis: The Crosstalk Between Macrophages and T Cells in the Synovium

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease. Joint inflammation of RA is closely related to infiltration of immune cells, synovium hyperplasia, and superfluous secretion of proinflammatory cytokines, which lead to cartilage degradation and bone erosion. The joint synovium of RA patients contains a variety of immune cellular types, among which monocytes/macrophages and T cells are two essential cellular components. Monocytes/macrophages can recruit and promote the differentiation of T cells into inflammatory phenotypes in RA synovium. Similarly, different subtypes of T cells can recruit monocytes/macrophages and promote osteoblast differentiation and production of inflammatory cytokines. In this review, we will discuss how T cell-monocyte/macrophage interactions promote the development of RA, which will provide new perspectives on RA pathogenesis and the development of targeted therapy.

Safety and Efficacy of Poseltinib, Bruton's Tyrosine Kinase Inhibitor, in Patients With Rheumatoid Arthritis: A Randomized, Double-blind, Placebo-controlled, 2-part Phase II Study

OBJECTIVE

To evaluate the efficacy and safety of poseltinib (formerly LY3337641/HM71224), an irreversible covalent inhibitor of Bruton's tyrosine kinase in a 2-part, phase II trial (RAjuvenate; ClinicalTrials.gov: NCT02628028) in adults with active rheumatoid arthritis (RA).

METHODS

In Part A, 36 patients with mildly active RA were randomized 1:1:1:1 to oral poseltinib 5, 10, or 30 mg or placebo once daily for 4 weeks to assess safety and tolerability. No safety signals precluded moving to Part B, where 250 patients with moderate-to-severe RA were randomized 1:1:1:1 to oral poseltinib 5 mg (n = 63), 10 mg (n = 62), or 30 mg (n = 63), or placebo (n = 62) once daily for 12 weeks. Parts A and B permitted stable doses of background disease-modifying antirheumatic drugs. The primary endpoint in Part B was proportion of patients achieving 20% improvement in American College of Rheumatology criteria (ACR20) at Week 12. Logistic regression compared each poseltinib dose to placebo for primary and secondary endpoints. Nonresponder imputation was used for missing data.

RESULTS

After interim analysis showed low likelihood of demonstrating significant efficacy, the sponsor discontinued Part B of the study. One hundred and eighty-nine (76%) patients completed 12 weeks in Part B; 61 discontinued study treatment (27 [44%] due to study termination by sponsor). There was no statistically significant difference in ACR20 response between any dose of poseltinib and placebo at Week 12 (P > 0.05 for all comparisons). Five serious adverse events occurred (n = 2, placebo; n = 3, 30 mg); there was 1 death due to a fall.

CONCLUSION

While no safety findings precluded continuation, the study was terminated after interim data demonstrated low likelihood of benefit in RA.

Activity Prediction of Small Molecule Inhibitors for Antirheumatoid Arthritis Targets Based on Artificial Intelligence

Rheumatoid arthritis (RA) is a chronic autoimmune disease, which is compared to "immortal cancer" in industry. Currently, SYK, BTK, and JAK are the three major targets of protein tyrosine kinase for this disease. According to existing research, marketed and research drugs for RA are mostly based on single target, which limits their efficacy. Therefore, designing multitarget or dual-target inhibitors provide new insights for the treatment of RA regarding of the specific association between SYK, BTK, and JAK from two signal transduction pathways. In this study, machine learning (XGBoost, SVM) and deep learning (DNN) models were combined for the first time to build a powerful integrated model for SYK, BTK, and JAK. The predictive power of the integrated model was proved to be superior to that of a single classifier. In order to accurately assess the generalization ability of the integrated model, comprehensive similarity analysis was performed on the training and the test set, and the prediction accuracy of the integrated model was specifically analyzed under different similarity thresholds. External validation was conducted using single-target and dual-target inhibitors, respectively. Results showed that our model not only obtained a high recall rate (97%) in single-target prediction, but also achieved a favorable yield (54.4%) in dual-target prediction. Furthermore, by clustering dual-target inhibitors, the prediction performance of model in various classes were proved, evaluating the applicability domain of the model in the dual-target drug screening. In summary, the integrated model proposed is promising to screen dual-target inhibitors of SYK/JAK or BTK/JAK as RA drugs, which is beneficial for the clinical treatment of rheumatoid arthritis.

Investigation of Potential Drug-Drug Interactions between Peficitinib (ASP015K) and Methotrexate in Patients with Rheumatoid Arthritis

BACKGROUND

Methotrexate is frequently used to treat rheumatoid arthritis. Peficitinib (ASP015K; Smyraf®), an oral Janus kinase inhibitor indicated for the treatment of rheumatoid arthritis, may be coadministered with methotrexate.

OBJECTIVE

The objective of this study was to investigate potential drug-drug interactions of peficitinib with methotrexate and the short-term safety of coadministration.

PATIENTS AND METHODS

This phase I, open-label, single-sequence study included patients with rheumatoid arthritis taking a stable dose of methotrexate. Patients received their prescribed methotrexate dose (Day 1) and then peficitinib (100 mg) twice daily from Day 3 until the morning of Day 9; a second methotrexate dose was coadministered with peficitinib on Day 8. Serial blood samples were collected for methotrexate concentration after dosing on Days 1 (methotrexate alone) and 8 (methotrexate plus peficitinib) and for peficitinib concentration after dosing on Days 7 (peficitinib alone) and 8 (methotrexate plus peficitinib). Pre-dose concentrations of peficitinib were measured (Days 3-8).

RESULTS

Peficitinib concentrations reached steady state on Day 5. Administration of peficitinib did not result in changes to methotrexate area under the concentration-time curve from time zero to infinity or maximum observed concentration following a methotrexate dose (15-25 mg), and there was no significant effect of methotrexate (15-25 mg) on peficitinib area under the concentration-time curve within a 12-hour dosing interval. There were no new tolerability or safety signals after coadministration of peficitinib and methotrexate. One patient experienced two serious adverse events and withdrew from the study without receiving peficitinib.

CONCLUSIONS

Pharmacokinetic results showed no significant interactions between peficitinib and methotrexate. CLINICALTRIALS.

GOV IDENTIFIER

NCT01754805.

Pancreatic Effects of a Bruton's Tyrosine Kinase Small-molecule Inhibitor in Rats Are Strain-dependent

Inhibitors of Bruton's tyrosine kinase (BTK) are under development as potential therapies for various autoimmune diseases. In repeat-dose toxicity studies, small-molecule BTK inhibitors (BTKi) have been reported to cause a constellation of histologic effects at the pancreatic endocrine-exocrine interface in male rats; however, similar findings were not reported in other species. Since the BTKi-induced pancreatic effect is morphologically similar to well-documented spontaneous changes (predominantly characterized by insular/peri-insular hemorrhage, pigment deposition, chronic inflammation, and fibrosis) that are known to vary by rat strain, we investigated potential strain-dependent differences in the pancreatic effects of a small-molecule BTKi, LY3337641. Following 13 weeks of LY3337641 treatment, Crl:CD(SD) rats were most sensitive, Crl:WI(Han) rats were of intermediate sensitivity, and Hsd:SD rats were least sensitive. These strain differences appear to be related to differences in rate of weight gain across strains and sexes; however, a definitive mechanism was not determined. This study demonstrated that BTKi-induced pancreatic effects were highly dependent on rat strain and correlated with differences in the incidence and severity of the spontaneous background change. When considered with the lack of pancreas effects in nonrat species, these changes in rats are unlikely predictive of similar changes in humans administered a BTK inhibitor.

Molecular dynamics and integrated pharmacophore-based identification of dual [Formula: see text] inhibitors

Despite increase in the understanding of the pathogenesis of rheumatoid arthritis (RA), it remains a tough challenge. The advent of kinases involved in key intracellular pathways in pathogenesis of RA may provide a new phase of drug discovery for RA. The present study is aimed to identify dual JAK3/[Formula: see text] inhibitors by developing an optimum pharmacophore model integrating the information revealed by ligand-based pharmacophore models and structure-based pharmacophore models (SBPMs). For JAK3 inhibitors, the addition of an aromatic ring feature and for [Formula: see text] the addition of a hydrophobic feature proposed by SBPMs lead to five-point pharmacophore (i.e., AADHR.54 (JAK3)) and six-point pharmacophore (i.e., AAAHRR.45 ([Formula: see text])). The obtained pharmacophores were validated and used for virtual screening and then for docking-based screening. Molecules were further evaluated for ADME properties, and their docked protein complexes were subjected to MM-GBSA energy calculations and molecular dynamic simulations. The top two hit compounds with novel scaffolds 2-oxo-1,2-dihydroquinoline and benzo[d]oxazole showed inhibitory activity for JAK3 and [Formula: see text].

Innate immune cells for immunotherapy of autoimmune and cancer disorders

Modulation of the immune system has been widely targeted for the treatment of several immune-related diseases, such as autoimmune disorders and cancer, due to its crucial role in these pathologies. Current available therapies focus mainly on symptomatic treatment and are often associated with undesirable secondary effects. For several years, remission of disease and subsequently recovery of immune homeostasis has been a major goal for immunotherapy. Most current immunotherapeutic strategies are aimed to inhibit or potentiate directly the adaptive immune response by modulating antibody production and B cell memory, as well as the effector potential and memory of T cells. Although these immunomodulatory approaches have shown some success in the clinic with promising therapeutic potential, they have some limitations related to their effectiveness in disease models and clinical trials, as well as elevated costs. In the recent years, a renewed interest has emerged on targeting innate immune cells for immunotherapy, due to their high plasticity and ability to exert a potent and extremely rapid response, which can influence the outcome of the adaptive immune response. In this review, we discuss the immunomodulatory potential of several innate immune cells, as well as they use for immunotherapy, especially in autoimmunity and cancer.

p-Coumaric acid, a dietary polyphenol ameliorates inflammation and curtails cartilage and bone erosion in the rheumatoid arthritis rat model

This study was designed to explore the underlying mechanism of p-coumaric acid (CA), a dietary polyphenol in adjuvant-induced arthritis (AIA) rat model with reference to synovitis and osteoclastogenesis. Celecoxib (COX-2 selective inhibitor) (5 mg/kg b.wt) was used as a reference drug. CA remarkably suppressed the paw edema, body weight loss and inflammatory cytokine and chemokine levels (TNF-α, IL-1β, IL-6, and MCP-1) in serum and ankle joint of arthritic rats. Consistently, CA reduced the expression of osteoclastogenic factors (RANKL and TRAP), pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, and IL-17), and inflammatory enzymes (iNOS and COX-2) in arthritic rats. However, OPG expression was found elevated. Besides, the abundance of transcription factors (NF-κB-p65, and p-NF-κB-p65, NFATc-1, and c-Fos) and MAP kinases (JNK, p-JNK, and ERK1/2) expression was alleviated in CA administered arthritic rats. In addition, CA truncated osteoclastogenesis by regulating the RANKL/OPG imbalance in arthritic rats and suppressing the RANKL-induced NFATc-1 and c-Fos expression in vitro. Radiological (CT and DEXA scan) and histological assessments authenticated that CA inhibited TRAP, bone destruction and cartilage degradation in association with enhanced bone mineral density. Taken together, our findings suggest that CA demonstrated promising anti-arthritic effect and could prove useful as an alternative drug in RA therapeutics. © 2017 BioFactors, 43(5):698-717, 2017.

Baseline JAK phosphorylation profile of peripheral blood leukocytes, studied by whole blood phosphospecific flow cytometry, is associated with 1-year treatment response in early rheumatoid arthritis

Background

We found recently that baseline signal transducer and activator of transcription 3 phosphorylation in peripheral blood CD4⁺ T cells of patients with early rheumatoid arthritis (RA) is associated with treatment response to synthetic disease-modifying antirheumatic drugs (DMARDs). This prompted us to study the baseline phosphorylation profiles of Janus kinases (JAKs) in blood leukocytes with respect to treatment response in early RA.

Methods

Thirty-five DMARD-naïve patients with early RA provided blood samples for whole blood flow cytometric determination of phosphorylation of JAKs in CD4⁺ and CD8⁺ T cells, CD19⁺ B cells, and CD14⁺ monocytes. Treatment response was determined after 1 year of treatment with synthetic DMARDs, with remission defined as absence of tender and swollen joints and normal erythrocyte sedimentation rate. Exact logistic regression was used to investigate the association of baseline variables with treatment response. Ninety-five percent CIs of means were estimated by bias-corrected bootstrapping.

Results

High JAK3 phosphorylation in CD4⁺ and CD8⁺ T cells, CD19⁺ B cells, and CD14⁺ monocytes and low JAK2 phosphorylation in CD14⁺ monocytes were significantly associated with remission following treatment with synthetic DMARDs.

Conclusions

Baseline JAK phosphorylation profile in peripheral blood leukocytes may provide a means to predict treatment response achieved by synthetic DMARDs among patients with early RA.

Discovery of N-(3-(5-((3-acrylamido-4-(morpholine-4-carbonyl)phenyl)amino)-1-methyl-6-oxo-1,6-dihydropyridin-3-yl)-2-methylphenyl)-4-(tert-butyl)benzamide (CHMFL-BTK-01) as a highly selective irreversible Bruton's tyrosine kinase (BTK) inhibitor

Currently there are several irreversible BTK inhibitors targeting Cys481 residue under preclinical or clinical development. However, most of these inhibitors also targeted other kinases such as BMX, JAK3, and EGFR that bear the highly similar active cysteine residues. Through a structure-based drug design approach, we discovered a highly potent (IC₅₀: 7 nM) irreversible BTK inhibitor compound 9 (CHMFL-BTK-01), which displayed a high selectivity profile in KINOMEscan (S score (35) = 0.00) among 468 kinases/mutants at the concentration of 1 μM. Compound 9 completely abolished BMX, JAK3 and EGFR's activity. Both X-ray crystal structure and cysteine-serine mutation mediated rescue experiment confirmed 9's irreversible binding mode. 9 also potently inhibited BTK Y223 auto-phosphorylation (EC₅₀: <30 nM), arrested cell cycle in G0/G1 phase and induced apoptosis in U2932 and Pfeiffer cells. We believe these features would make 9 a good pharmacological tool to study the BTK related pathology.

A novel JAK inhibitor, peficitinib, demonstrates potent efficacy in a rat adjuvant-induced arthritis model

The Janus kinase (JAK) family of tyrosine kinases is associated with various cytokine receptors. JAK1 and JAK3 play particularly important roles in the immune response, and their inhibition is expected to provide targeted immune modulation. Several oral JAK inhibitors have recently been developed for treating autoimmune diseases, including rheumatoid arthritis (RA). Here, we investigated the pharmacological effects of peficitinib (formerly known as ASP015K), a novel, chemically synthesized JAK inhibitor. We found that peficitinib inhibited JAK1 and JAK3 with 50% inhibitory concentrations of 3.9 and 0.7 nM, respectively. Peficitinib also inhibited IL-2-dependent T cell proliferation in vitro and STAT5 phosphorylation in vitro and ex vivo. Furthermore, peficitinib dose-dependently suppressed bone destruction and paw swelling in an adjuvant-induced arthritis model in rats via prophylactic or therapeutic oral dosing regimens. Peficitinib also showed efficacy in the model by continuous intraperitoneal infusion. Area under the concentration versus time curve (AUC) at 50% inhibition of paw swelling via intraperitoneal infusion was similar to exposure levels of AUC at 50% inhibition via oral administration, implying that AUC might be important for determining the therapeutic efficacy of peficitinib. These data suggest that peficitinib has therapeutic potential for the oral treatment of RA.

Chemical JAK inhibitors for the treatment of rheumatoid arthritis

INTRODUCTION

Considerable advances in the treatment of rheumatoid arthritis (RA) have been made following the advent of biological disease-modifying anti-rheumatic drugs (DMARDs). However, biological DMARDs require intravenous or subcutaneous injection and some patients fail to respond to these drugs or lose their primary response. Currently, Janus kinase (JAK) inhibitors have been developed as a new class of DMARD that inhibits the non-receptor tyrosine kinase family JAK involved in intracellular signaling of various cytokines and growth factors. Areas covered: Several JAK inhibitors such as tofacitinib and baricitinib are oral synthetic DMARD that inhibit JAK1, 2 and 3. Both drugs have shown feasible efficacy and tolerable safety. In this article, efficacy and adverse events from the phase III trials of JAK inhibitors are overviewed. In addition, pharmacokinetics and mechanism of action of JAK inhibitors in relevance to efficacy and adverse events are covered. Expert opinion: JAK inhibitors are novel therapies for RA that inhibit multiple cytokines and signaling pathways. Further studies are needed to determine their risk-benefit ratio and selection of the most appropriate patients for such therapy.

Potent anti-inflammatory effects of the narrow spectrum kinase inhibitor RV1088 on rheumatoid arthritis synovial membrane cells

Background and Purpose

To investigate whether a narrow spectrum kinase inhibitor RV1088, which simultaneously targets specific MAPKs, Src and spleen tyrosine kinase (Syk), is more effective at inhibiting inflammatory signalling in rheumatoid arthritis (RA) than single kinase inhibitors (SKIs).

Experimental Approach

elisas were used to determine the efficacy of RV1088, clinically relevant SKIs and the pharmaceutical Humira on pro-inflammatory cytokine production by activated RA synovial fibroblasts, primary human monocytes and macrophages, as well as spontaneous cytokine synthesis by synovial membrane cells from RA patients. In human macrophages, RNAi knockdown of individual kinases was used to reveal the effect of inhibition of kinase expression on cytokine synthesis.

Key Results

RV1088 reduced TNF-α, IL-6 and IL-8 production in all individual activated cell types with low, nM, IC₅₀s. SKIs, and combinations of SKIs, were significantly less effective than RV1088. RNAi of specific kinases in macrophages also caused only modest inhibition of pro-inflammatory cytokine production. RV1088 was also significantly more effective at inhibiting IL-6 and IL-8 production by monocytes and RA synovial fibroblasts compared with Humira. Finally, RV1088 was the only inhibitor that was effective in reducing TNF-α, IL-6 and IL-8 synthesis in RA synovial membrane cells with low nM IC₅₀s.

Conclusions and Implications

This study demonstrates potent anti-inflammatory effect of RV1088, highlighting that distinct signalling pathways drive TNF-α, IL-6 and IL-8 production in the different cell types found in RA joints. As such, targeting numerous signalling pathways simultaneously using RV1088 could offer a more powerful method of reducing inflammation in RA than targeting individual kinases.

Prolonged tumor necrosis factor α primes fibroblast-like synoviocytes in a gene-specific manner by altering chromatin

OBJECTIVE

During the course of rheumatoid arthritis (RA), fibroblast-like synoviocytes (FLS) are chronically exposed to an inflammatory milieu. The purpose of this study was to test the hypothesis that prolonged exposure of FLS to tumor necrosis factor α (TNFα) augments inflammatory responses to secondary stimuli (priming effect).

METHODS

FLS obtained from RA patients were exposed to TNFα for 3 days and were then stimulated with interferons (IFNs). Expression of IFN target genes was measured by real-time quantitative reverse transcription-polymerase chain reaction analysis and enzyme-linked immunosorbent assay. Total STAT-1 protein and IFN-mediated STAT-1 activation were evaluated by Western blotting. Total histone levels, histone acetylation, and NF-κB p65 and RNA polymerase II (Pol II) recruitment were measured at the CXCL10 promoter (encodes IFNγ-inducible 10-kd protein [IP-10]) by chromatin immunoprecipitation assays.

RESULTS

Prolonged pre-exposure of FLS to TNFα enhanced the magnitude and extended the kinetics of CXCL10/IP-10, CXCL9, and CXCL11 production upon subsequent IFN stimulation. This phenotype was retained over a period of days, even after the removal of TNFα. Prolonged TNFα exposure decreased histone levels, increased acetylation of the remaining histones, and heightened recruitment of NF-κB p65 and Pol II to the CXCL10 promoter. In parallel, an increase in intracellular STAT-1 led to amplification of IFN-induced STAT-1 activation.

CONCLUSION

Our study reveals a novel pathogenic function of TNFα, namely, prolonged and gene-specific priming of FLS for enhanced transcription of inflammatory chemokine genes due to the priming of chromatin, the sustained activation of NF-κB, and the amplification of STAT-1 activation downstream of IFNs. These data also suggest that FLS gain an "inflammatory memory" upon prolonged exposure to TNFα.

Small-molecule inhibitors for autoimmune arthritis: success, failure and the future

Treatment of patients with aggressive autoimmune arthritis, such as rheumatoid arthritis (RA), is a considerable challenge for physicians, particularly rheumatologists. Because of the nature of autoimmune arthritis, effective and complete suppression of disease activity has been the primary therapeutic goal. Although currently available disease-modifying antirheumatic drugs (DMARDs) can successfully control the disease progression in a large proportion of patients, the benefit/risk ratio is not very much satisfied. The introduction of biologic agents such as anti-tumor necrosis factor-α, anti-interleukin-6, and anti-CD20 brings significant help to those patients with an inadequate response to treatment with DMARDs. In considering the limitation of currently available DMARDs and biologics, the development of new DMARDs, small-molecule inhibitors (SMIs), has recently emerged. In the past few years, a great volume of knowledge has been revealed from the experience of examining the usefulness of several SMIs for therapeutics of autoimmune arthritis. This paper addresses the up-to-date knowledge regarding autoimmune arthritis, therapeutics, findings from recently developed SMIs and the benefits and drawbacks of the development of SMIs. In addition, perspectives on the future development of SMIs for autoimmune arthritis will be described and discussed.

Therapeutic targets for rheumatoid arthritis: Progress and promises

Recent therapeutic advancements in understanding of molecular and cellular mechanisms of rheumatoid arthritis (RA) have highlighted the strategies that aim to inhibit the harmful effects of up-regulated cytokines or other inflammatory mediators and to inhibit their associated signaling events. The utility of cytokine as therapeutic targets in RA has been unequivocally demonstrated by the success of tumor necrosis factor (TNF)-α blockade in clinical practice. Partial and non-responses to TNF-α blocking agents, however, together with the increasing clinical drive to remission induction, requires that further therapeutic targets be identified. Numerous proinflammatory mediators with their associated cell signaling events have now been demonstrated in RA, including interleukin (IL)-1 and IL-12 superfamilies. Continued efforts are ongoing to target IL-6, IL-15 and IL-17 in clinical trials with promising data emerging. In the present review, we focus on IL-7, IL-18, IL-32 and IL-10 family of cytokines (IL-19, IL-20 and IL-22) as they are implicated in contributing to the pathogenesis of RA, which could be targeted and offer new therapeutic options for RA therapy. Recent evidences also suggest that multiligand receptor for advanced glycation end products (RAGE), several adipokines and various components of immune system play a critical role in the pathophysiology of RA; therefore we have also highlighted them as therapeutic targets for RA therapy. Components of subcellular pathways, involve in nuclear transcription factor (NF)-κB, mitogen-activated protein kinases (MAPKs) and the Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway have also been discussed and offer several novel potential therapeutic opportunities for RA.

PI3K-δ and PI3K-γ inhibition by IPI-145 abrogates immune responses and suppresses activity in autoimmune and inflammatory disease models

Phosphoinositide-3 kinase (PI3K)-δ and PI3K-γ are preferentially expressed in immune cells, and inhibitors targeting these isoforms are hypothesized to have anti-inflammatory activity by affecting the adaptive and innate immune response. We report on a potent oral PI3K-δ and PI3K-γ inhibitor (IPI-145) and characterize this compound in biochemical, cellular, and in vivo assays. These studies demonstrate that IPI-145 exerts profound effects on adaptive and innate immunity by inhibiting B and T cell proliferation, blocking neutrophil migration, and inhibiting basophil activation. We explored the therapeutic value of combined PI3K-δ and PI3K-γ blockade, and IPI-145 showed potent activity in collagen-induced arthritis, ovalbumin-induced asthma, and systemic lupus erythematosus rodent models. These findings support the hypothesis that inhibition of immune function can be achieved through PI3K-δ and PI3K-γ blockade, potentially leading to significant therapeutic effects in multiple inflammatory, autoimmune, and hematologic diseases.