Immunotherapeutic implication of IL-6 blockade

Cytokines in Thyroid-Associated Ophthalmopathy

Thyroid-associated ophthalmopathy (TAO), also known as thyroid eye disease (TED) or Graves' orbitopathy (GO), is a complex autoimmune condition causing visual impairment, disfigurement, and harm to patients' physical and mental health. The pathogenesis of TAO has not been fully elucidated, and the mainstream view is that coantigens shared by the thyroid and orbit trigger remodeling of extraocular muscles and orbital connective tissues through an inflammatory response. In recent years, cytokines and the immune responses they mediate have been crucial in disease progression, and currently, common evidence has shown that drugs targeting cytokines, such as tocilizumab, infliximab, and adalimumab, may be novel targets for therapy. In this review, we summarize the research development of different cytokines in TAO pathogenesis in the hope of discovering new therapeutic targets.

Systemic inflammation in COVID‐19 patients may induce various types of venous and arterial thrombosis: A systematic review

COVID‐19 is a global pandemic with a daily increasing number of affected individuals. Thrombosis is a severe complication of COVID‐19 that leads to a worse clinical course with higher rates of mortality. Multiple lines of evidence suggest that hyperinflammation plays a crucial role in disease progression. This review compiles clinical data of COVID‐19 patients who developed thrombotic complications to investigate the possible role of hyperinflammation in inducing hypercoagulation. A systematic literature search was performed using PubMed, Embase, Medline and Scopus to identify relevant clinical studies that investigated thrombotic manifestations and reported inflammatory and coagulation biomarkers in COVID‐19 patients. Only 54 studies met our inclusion criteria, the majority of which demonstrated significantly elevated inflammatory markers. In the cohort studies with control, D‐dimer was significantly higher in COVID‐19 patients with thrombosis as compared to the control. Pulmonary embolism, deep vein thrombosis and strokes were frequently reported which could be attributed to the hyperinflammatory response associated with COVID‐19 and/or to the direct viral activation of platelets and endothelial cells, two mechanisms that are discussed in this review. It is recommended that all admitted COVID‐19 patients should be assessed for hypercoagulation. Furthermore, several studies have suggested that anticoagulation may be beneficial, especially in hospitalized non‐ICU patients. Although vaccines against SARS‐CoV‐2 have been approved and distributed in several countries, research should continue in the field of prevention and treatment of COVID‐19 and its severe complications including thrombosis due to the emergence of new variants against which the efficacy of the vaccines is not yet clear.

Not all bad: Drug-induced interstitial pneumonia in DLBCL patients is potentially fatal but could be linked to better survival

BACKGROUND

Interstitial pneumonitis (IP), a fatal complication of DLBCL treatment, can bring great challenges to clinicians. We retrospectively investigated clinical characteristics and risk factors of previous IP patients, and analyzed their survival data.

METHODS

556 DLBCL patients receiving CHOP-like regimens were enrolled between 2013 and 2018 in Sichuan Cancer Hospital.

FINDINGS

The IP incidences were 4.9 % (27/556), 1.1 % (2/186), 5.2 % (10/191) and 8.4 % (15/179) in CHOP, R-CHOP and R-CDOP groups respectively (P = 0.005). When IP was diagnosed, monocyte and IL-6 were significantly higher while CD4 and CD4/CD8 significantly lower compared to baseline. 81.5 % (22/27) of IP patients were pathogen-negative with good response to glucocorticoid monotherapy. Only one patient died while the others recovered from IP and subsequently underwent previous chemotherapy. 19.2 % (5/26) of IP patients experienced IP recurrence, likely due to the reason of lower initial dose or faster withdrawal speed of glucocorticoid. Multivariate analysis identified male, in addition to G-CSF, rituximab and pegylated liposomal doxorubicin as risk factors. The 3-year PFS and OS were 74.1 % and 46.9 % respectively for patients with IP.

INTERPRETATION

We suggest that IL-6, monocyte and CD4 should be monitored closely, especially in R-CHOP/R-CDOP group. Sufficient initial dose and slow decrease of glucocorticoid based on radiographic remissions were critical strategies to reduce IP recurrence. We speculate that drug-induced immune imbalance could be trigger of developing IP, causing a lower intensity cytokine storm, resulting in a potential immunotherapy. This complication might bring benefit in patients' survival through a mechanism similar to PD-1.

PROTACs: New method to degrade transcription regulating proteins

Transcription is the fundamental process in all living organisms. A variety of important proteins, such as NRs, BETs, HDACs and many others are involved in transcription process. In general, overexpression of these proteins would cause many diseases. Some approved therapeutics employed inhibitors to regulate the transcription process, however, the results are far from satisfying. Therefore, it is in high demand to develop new technology to improve the therapeutic effects. In recent years, proteolysis-targeting chimaera (PROTAC) turned out to be a novel efficient therapeutic method to treat various diseases which were caused by proteins overexpression. PROTAC molecules are bifunctional small molecules that simultaneously bind a target protein and an E3-ubiquitin ligase, thus causing ubiquitination and subsequent degradation of the target protein by the proteasome. In contrast to traditional inhibitors, PROTACs showed higher efficiency to tackle the diseases which were caused by protein overexpression due to their excellent performance for degrading target proteins in transcription regulation. In this review, 29 kinds of PROTACs targeting transcription regulator proteins are summarized, and meanwhile the advantages of PROTACs are highlighted. Furthermore, several examples of PROTACs regulating the transcription for the treatment of diseases and functioning as tools for biological research are also disscussed.

Orthopaedic Surgery Elicits a Systemic Anti-Inflammatory Signature

Little information is available on the functional activity of leukocytes after arthroplasty or the expansion of populations with immune suppressive properties during the acute post-operative period. Synovial fluid and matched pre- and post-surgical blood samples were collected from total hip and knee arthroplasty patients (THA and TKA, respectively) to examine the impact of surgery on peripheral blood leukocyte frequency, bactericidal activity, and inflammatory mediator expression. For spinal surgeries, inflammatory mediator production by peripheral blood mononuclear cells (PBMCs) pre- and post-surgery was examined. An expansion of immune suppressive granulocytic myeloid-derived suppressor cells (G-MDSCs) was observed following arthroplasty, which correlated with significantly increased serum interleukin-10 (IL-10) levels. Analysis of synovial fluid from THA and TKAs revealed reduced granulocyte colony-stimulating factor (G-CSF) and soluble CD40 ligand (sCD40L) and increased interleukin-6 (IL-6), monocyte chemoattractant protein 2 (CCL2) and Fms-like tyrosine kinase 3 ligand (Flt-3L) compared to pre- and post-surgical serum. For the spinal surgery cohort, stimulation of PBMCs isolated post-surgery with bacterial antigens produced significantly less pro-inflammatory (IL-1α, IL-1β, interleukin-1 receptor antagonist (IL-1RA), IL-12p40, growth-related oncogene-α/GRO-α (CXCL1) and 6Ckine (CCL21)) and more anti-inflammatory/tissue repair mediators (IL-10, G-CSF and granulocyte-macrophage colony-stimulating factor (GM-CSF)) compared to PBMCs recovered before surgery. The observed bias towards systemic anti-inflammatory changes without concomitant increases in pro-inflammatory responses may influence susceptibility to infection following orthopaedic surgery in the context of underlying co-morbidities or risk factors.

Effect of Danshen on TLR2-triggered inflammation in macrophages

BACKGROUND

Danshen (Salvia Miltiorrhiza Radix et Rhizoma) is a valued herbal plant widely used to treat cardiovascular diseases in Asian countries. In modern medicine, innate immunity-induced inflammation is considered a risk factor for cardiovascular diseases. However, little is known about the anti-inflammatory effects and molecular mechanism of Danshen.

PURPOSE

To evaluate the molecular mechanisms of Danshen on Toll-like receptor (TLR) 2-triggered inflammation in macrophages and identify its bioactive components.

METHODS

Pam3CSK4-stimulated bone marrow-derived macrophages (BMMs) were treated with Danshen water extract (DSE), and the levels of proinflammatory cytokines (interleukin (IL)-6, IL-12 and tumor necrosis factor (TNF)-α) were measured by both real-time quantitative PCR (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA). RNA sequencing (RNA-seq)-based bioinformatics analyses were applied to reveal the novel molecular mechanisms of DSE, followed by western blotting for verification. Additionally, HPLC-UV analysis along with bioassays was performed to identify the bioactive ingredients of DSE.

RESULTS

The results of RT-qPCR and ELISA showed that DSE significantly inhibited proinflammatory cytokine expression in a dose-dependent manner. Transcriptome analyses revealed that a wider panel of inflammatory cytokines responded to the regulatory effect of DSE, and that the TNF signaling pathway might have played a vital role. Western blotting data confirmed the involvement of extracellular signal-regulated protein kinases (ERK) and Jun N-terminal Kinase (JNK) related singling pathway. Among the seven components identified in DSE, Danshensu (DSS) and protocatechuic aldehyde (PA) were confirmed as bioactive ones with anti-inflammatory effects.

CONCLUSION

DSE showed a promising effect against TLR2-triggered inflammation associated with the inhibition of the TNF cascade down-streamed mitogen-activated protein kinase (MAPK) signaling pathway, in which IL-6 acts as the key effective molecule, and ERK and JNK phosphorylation was inhibited. Notably, DSS and PA were considered bioactive components with anti-inflammatory bioactivity.

CD154 Induces Interleukin-6 Secretion by Kidney Tubular Epithelial Cells under Hypoxic Conditions: Inhibition by Chloroquine

Inflammation is a major contributor to tubular epithelium injury in kidney disorders, and the involvement of blood platelets in driving inflammation is increasingly stressed. CD154, the ligand of CD40, is one of the mediators supporting platelet proinflammatory properties. Although hypoxia is an essential constituent of the inflammatory reaction, if and how platelets and CD154 regulate inflammation in hypoxic conditions remain unclear. Here, we studied the control by CD154 of the proinflammatory cytokine interleukin- (IL-) 6 secretion in short-term oxygen (O₂) deprivation conditions, using the HK-2 cell line as a kidney tubular epithelial cell (TEC) model. IL-6 secretion was markedly stimulated by CD154 after 1 to 3 hours of hypoxic stress. Both intracellular IL-6 expression and secretion were stimulated by CD154 and associated with a strong upregulation of IL-6 mRNA and increased transcription. Searching for inhibitors of CD154-mediated IL-6 production by HK-2 cells in hypoxic conditions, we observed that chloroquine, a drug that has been repurposed as an anti-inflammatory agent, alleviated this induction. Therefore, CD154 is a potent early stimulus for IL-6 secretion by TECs in O₂ deprivation conditions, a mechanism likely to take part in the deleterious inflammatory consequences of platelet activation in kidney tubular injury. The inhibition of CD154-induced IL-6 production by chloroquine suggests the potential usefulness of this drug as a therapeutic adjunct in conditions associated with acute kidney injury.

Humanization and Simultaneous Optimization of Monoclonal Antibody

Antibody humanization is an essential technology for reducing the potential risk of immunogenicity associated with animal-derived antibodies and has been applied to a majority of the therapeutic antibodies on the market. For developing an antibody molecule as a pharmaceutical at the current biotechnology level, however, other properties also have to be considered in parallel with humanization in antibody generation and optimization. This section describes the critical properties of therapeutic antibodies that should be sufficiently qualified, including immunogenicity, binding affinity, physicochemical stability, expression in host cells and pharmacokinetics, and the basic methodologies of antibody engineering involved. By simultaneously optimizing the antibody molecule in light of these properties, it should prove possible to shorten the research and development period necessary to identify a highly qualified clinical candidate and consequently accelerate the start of the clinical trial.

Modulating PCAF/GCN5 Immune Cell Function through a PROTAC Approach

P300/CBP-associated factor (PCAF) and general control nonderepressible 5 (GCN5) are closely related epigenetic proteins, each containing an acetyltransferase domain and a bromodomain. Consistent with reported roles for these proteins in immune function, we find that PCAF-deficient macrophages exhibit a markedly reduced ability to produce cytokines upon stimulation with lipopolysaccharide (LPS). Investigating the potential to target this pathway pharmacologically, we show that chemical inhibition of the PCAF/GCN5 bromodomains is insufficient to recapitulate the diminished inflammatory response of PCAF-deficient immune cells. However, by generating the first PCAF/GCN5 proteolysis targeting chimera (PROTAC), we identify small molecules able to degrade PCAF/GCN5 and to potently modulate the expression of multiple inflammatory mediators in LPS-stimulated macrophages and dendritic cells. Our data illustrate the power of the PROTAC approach in the context of multidomain proteins, revealing a novel anti-inflammatory therapeutic opportunity for targeting PCAF/GCN5.

[Interleukin-6 inhibition as a potential therapeutic target in rheumatic diseases]

As a pro-inflammatory cytokine, the 21-kDa glycoprotein interleukin-6 (IL-6) plays a crucial role in the initiation of acute inflammation, as well in the perpetuation of a chronic inflammatory immune response. Thus, IL-6 might be involved in the pathogenesis of various autoimmune diseases. So far, the IL-6-rezeptor-antibody tocilizumab (TCZ, RoActemtra®) is the only approved drug for the treatment of IL-6-mediated disease, including rheumatoid arthritis (RA), systemic juvenile idiopathic (sJIA) and polyarticular juvenile arthritis (pJiA), as well as Castleman's disease (in Japan only). In recent years, an emerging number of case reports and small uncontrolled case series have reported on the successful treatment of various other chronic inflammatory diseases, which has resulted in the idea of a broad therapeutic potential for IL-6 blockade. Numerous IL-6 targets are currently in phase II/III study programs for RA as well as for other indications. This review focuses on the development of tocilizumab and other IL-6 targets as a therapeutic option for various diseases in rheumatology.

Immunotherapeutic Biologic Agents in Autoimmune and Autoinflammatory Diseases

In recent decades, innovative strategies to treat patients with inflammatory, immunologically based diseases have advanced in concert with our increased understanding of molecular immunology. Recognition of the spectrum and pathophysiology of autoimmune and autoinflammatory disorders has allowed for the development of cutting-edge therapies for such patients. In this review, key immunotherapeutic approaches for treating inflammatory autoimmune disorders, such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE), as well as genetic autoinflammatory diseases, such as cryopyrin associated periodic syndromes, are addressed. Indications, risks and additional considerations in the use of these agents are reviewed.

Anti-citrullinated peptide antibodies and their value for predicting responses to biologic agents: a review

Anti-citrullinated peptide antibodies (ACPAs) play an important pathogenic role both at the onset and during the disease course. These antibodies precede the clinical appearance of rheumatoid arthritis (RA) and are associated with a less favorable prognosis, both clinically and radiologically. The objective of this work was to conduct a comprehensive review of studies published through September 2015 of ACPAs' role as a predictor of the therapeutic response to the biological agents in RA patients. The review also includes summary of the biology and detection of ACPAs as well as ACPAs in relation to joint disease and CV disease and the possible role of seroconversion. The reviews of studies examining TNF inhibitors and tocilizumab yielded negative results. In the case of rituximab, the data indicated a greater probability of clinical benefit in ACPA(+) patients versus ACPA(-) patients, as has been previously described for rheumatoid factor. Nonetheless, the effect is discreet and heterogeneous. Another drug that may have greater effectiveness in ACPA(+) patients is abatacept. Some studies have suggested that the drug is more efficient in ACPA(+) patients and that those patients show greater drug retention. In a subanalysis of the AMPLE trial, patients with very high ACPA titers who were treated with abatacept had a statistically significant response compared to patients with lower titers. In summary, the available studies suggest that the presence of or high titers of ACPA may predict a better response to rituximab and/or abatacept. Evidence regarding TNFi and tocilizumab is lacking. However, there is a lack of studies with appropriate designs to demonstrate that some drugs are superior to others for ACPA(+) patients.

Trauma in silico: Individual-specific mathematical models and virtual clinical populations

Trauma-induced critical illness is driven by acute inflammation, and elevated systemic interleukin-6 (IL-6) after trauma is a biomarker of adverse outcomes. We constructed a multicompartment, ordinary differential equation model that represents a virtual trauma patient. Individual-specific variants of this model reproduced both systemic inflammation and outcomes of 33 blunt trauma survivors, from which a cohort of 10,000 virtual trauma patients was generated. Model-predicted length of stay in the intensive care unit, degree of multiple organ dysfunction, and IL-6 area under the curve as a function of injury severity were in concordance with the results from a validation cohort of 147 blunt trauma patients. In a subcohort of 98 trauma patients, those with high-IL-6 single-nucleotide polymorphisms (SNPs) exhibited higher plasma IL-6 levels than those with low IL-6 SNPs, matching model predictions. Although IL-6 could drive mortality in individual virtual patients, simulated outcomes in the overall cohort were independent of the propensity to produce IL-6, a prediction verified in the 98-patient subcohort. In silico randomized clinical trials suggested a small survival benefit of IL-6 inhibition, little benefit of IL-1β inhibition, and worse survival after tumor necrosis factor-α inhibition. This study demonstrates the limitations of extrapolating from reductionist mechanisms to outcomes in individuals and populations and demonstrates the use of mechanistic simulation in complex diseases.

IL-10-overexpressing B cells regulate innate and adaptive immune responses

BACKGROUND

Distinct human IL-10-producing B-cell subsets with immunoregulatory properties have been described. However, the broader spectrum of their direct cellular targets and suppressive mechanisms has not been extensively studied, particularly in relation to direct and indirect IL-10-mediated functions.

OBJECTIVE

The aim of the study was to investigate the effects of IL-10 overexpression on the phenotype and immunoregulatory capacity of B cells.

METHODS

Primary human B cells were transfected with hIL-10, and IL-10-overexpressing B cells were characterized for cytokine and immunoglobulin production by means of specific ELISA and bead-based assays. Antigen presentation, costimulation capacity, and transcription factor signatures were analyzed by means of flow cytometry and quantitative RT-PCR. Effects of IL-10-overexpresing B cells on Toll-like receptor-triggered cytokine release from PBMCs, LPS-triggered maturation of monocyte-derived dendritic cells, and tetanus toxoid-induced PBMC proliferation were assessed in autologous cocultures.

RESULTS

IL-10-overexpressing B cells acquired a prominent immunoregulatory profile comprising upregulation of suppressor of cytokine signaling 3 (SOCS3), glycoprotein A repetitions predominant (GARP), the IL-2 receptor α chain (CD25), and programmed cell death 1 ligand 1 (PD-L1). Concurrently, their secretion profile was characterized by a significant reduction in levels of proinflammatory cytokines (TNF-α, IL-8, and macrophage inflammatory protein 1α) and augmented production of anti-inflammatory IL-1 receptor antagonist and vascular endothelial growth factor. Furthermore, IL-10 overexpression was associated with a decrease in costimulatory potential. IL-10-overexpressing B cells secreted less IgE and potently suppressed proinflammatory cytokines in PBMCs, maturation of monocyte-derived dendritic cells (rendering their profile to regulatory phenotype), and antigen-specific proliferation in vitro.

CONCLUSION

Our data demonstrate an essential role for IL-10 in inducing an immunoregulatory phenotype in B cells that exerts substantial anti-inflammatory and immunosuppressive functions.

Interleukin-6 receptor blockade enhances CD39+ regulatory T cell development in rheumatoid arthritis and in experimental arthritis

OBJECTIVE

The rationale for blocking interleukin-6 (IL-6) in rheumatoid arthritis (RA) lies chiefly in the proinflammatory effect of this cytokine. Few studies have evaluated the consequences of anti-IL-6 receptor (IL-6R) antibody treatment on Treg cells. This study was undertaken to elucidate the mechanism of action of anti-IL-6R antibody treatment by studying the effects on Treg cells in an experimental arthritis model and in patients with RA.

METHODS

Mice with collagen-induced arthritis (CIA) were treated with a mouse anti-IL-6R antibody (MR16-1), and changes in Treg, Th1, and Th17 cells were assessed at key time points during the course of the disease. Peripheral blood from 15 RA patients was collected on day 0 and after 3 months of tocilizumab treatment for flow cytometry analysis of Th17 and Treg cells.

RESULTS

In MR16-1-treated mice, Th17 cell frequencies were unchanged, whereas Treg cell frequencies were increased. The Treg cell phenotype showed marked changes, with an increase in the frequency of CD39+ Treg cells in the lymph nodes and spleen. Interestingly, similar CD39+ Treg cell expansion was observed in RA patients who were tocilizumab responders at 3 months, with no change in Th17 cell frequency. Moreover, fluorescence-activated cell-sorted CD39+ Treg cells from responder RA patients were functionally able to suppress the proliferation of conventional T cells.

CONCLUSION

In both CIA and RA, the frequency of functionally suppressive CD39+ Treg cells is increased as a result of anti-IL-6R treatment, whereas Th17 cells are unaffected. The modification of Treg cell frequency and phenotype may be one of the mechanisms involved in the therapeutic effect of IL-6 blockade in RA.

Influences of IL-6R antibody on PMMA bone cement-mediated expression of OPG and RANKL in synovial fibroblasts

Effect of interleukin-6 receptor (IL-6R) antibody on polymethyl methacrylate (PMMA) bone cement-mediated expression of osteoprotegerin (OPG) and receptor activator of nuclear factor-kappaB ligand (RANKL) in synovial fibroblasts was investigated. Synovial tissue obtained from total knee arthroplasty was digested and cultured. Inverted microscope was employed to observe the synovial cells and immunocytochemistry (SABC method) staining was used to identify synovial fibroblasts. This experiment was divided into three groups according to different culture media: PMMA group (75 μg/mL PMMA bone cement particles), IL-6R antibody group (10 ng/mL IL-6R antibody+75 μg/mL PMMA bone cement particles), and control group (no IL-6R antibody or PMMA bone cement particles). Influence of IL-6R antibody and PMMA on proliferation of synovial fibroblasts was measured by cell counting kit-8 (CCK-8). ELISA method was used to measure OPG and RANKL levels in culture solution. Fluorescence quantitative real-time PCR (FQ-PCR) was used to detect the expression of OPG and RANKL mRNA. After three consecutive passages, more than 95% of the primary synovial cells became long spindle fibroblast-like cells. SABC staining results showed that the fibroblast-like cells were negative for anti-CD68 antibody and positive for anti-vimentin antibody, with brown madder stained. CCK-8 test demonstrated that the absorbance (A) value at 450 nm was significantly lower in IL-6R antibody group than in PMMA group and control group (P<0.01), but there was no statistically significant difference in A value at 450 nm between the control group and PMMA group (P>0.05). Results of ELISA indicated that the expression of OPG was significantly higher in IL-6R antibody group than in PMMA group and control group (P<0.01). The expression of RANKL was inhibited (P<0.05), and the ratio of OPG/RANKL was significantly increased in IL-6R antibody group as compared with PMMA group and control group. There was no significant difference in the expression of OPG between control group and PMMA group (P>0.05), but the expression of RANKL was higher in PMMA group than in control group (P<0.05), and there was a significant difference in the ratio of OPG/RANKL between them (P<0.05). Results of FQ-PCR revealed the expression of RANKL mRNA was significantly inhibited (P<0.01) and the expression of OPG mRNA was significantly increased (P<0.01) in IL-6R antibody group as compared with PMMA group and control group. The expression of RANKL mRNA was higher in PMMA group than in control group (P<0.05), but the expression of OPG mRNA had no significant difference between them (P>0.05). IL-6R antibody could significantly increase the expression of OPG, but inhibit the expression of RANKL, which might provide a theoretical basis of molecular biology for the prevention and treatment of aseptic loosening of prosthesis.

Anti-tumor necrosis factor α targets protein kinase B/c-Akt-induced resistance of effector cells to suppression in juvenile idiopathic arthritis

OBJECTIVE

To determine whether therapeutic strategies that block interleukin-6 (IL-6) or tumor necrosis factor α (TNFα) can improve the responsiveness of Teff cells to suppression in patients with juvenile idiopathic arthritis (JIA).

METHODS

Synovial fluid mononuclear cells (SFMCs) from the inflamed joints of patients with JIA were cultured in the presence of etanercept or anti-IL-6 in vitro, and protein kinase B (PKB)/c-Akt activation and responsiveness to suppression were measured. In addition, the in vivo effects of TNFα blockade were investigated using peripheral blood mononuclear cells obtained from patients before and after the start of etanercept therapy.

RESULTS

In vitro treatment of SFMCs with anti-IL-6 led to improved Treg cell-mediated suppression of cell proliferation in some but not all patients. Blocking TNFα with etanercept, however, clearly enhanced suppression, especially that of CD8+ T cells. In the presence of etanercept, PKB/c-Akt activation of Teff cells was reduced, and cells became more susceptible to transforming growth factor β-mediated suppression, indicating that anti-TNFα directly targets resistant Teff cells.

CONCLUSION

This study is the first to show that anti-TNFα targets the resistance of Teff cells to suppression, resulting in improved regulation of inflammatory effector cells.

Humanization and simultaneous optimization of monoclonal antibody

Antibody humanization is an essential technology for reducing the potential risk of immunogenicity associated with animal-derived antibodies and has been applied to a majority of the therapeutic antibodies on the market. For developing an antibody molecule as a pharmaceutical at the current biotechnology level, however, other properties also have to be considered in parallel with humanization in antibody generation and optimization. This section describes the critical properties of therapeutic antibodies that should be sufficiently qualified, including immunogenicity, binding affinity, physiochemical stability, expression in host cells and pharmacokinetics, and the basic methodologies of antibody engineering involved. By simultaneously optimizing the antibody molecule in the light of these properties, it should prove possible to shorten the research and development period necessary to identify a highly qualified clinical candidate and consequently accelerate the start of the clinical trial.

Oncogene and non-oncogene addiction in inflammation-associated cancers

Many cancers originate in tissues that are chronically inflamed, and the inflammatory microenvironment is considered to promote the progression of malignancy, including initiation, growth, angiogenesis, invasion and metastasis. The molecular mechanism of inflammation-induced progression of cancers has been widely discussed. Oncogene and non-oncogene addiction have been proposed as two distinct but complementary theories to explain the initiation and development of cancers. Furthermore, they also play a role in cancer-associated inflammation. A solid understanding of oncogene and non-oncogene addiction in cancer-associated inflammatory microenvironments will help to exploit cancer drug targets for cancer prevention and clinical treatment.

Targeting interleukin-6 in inflammatory autoimmune diseases and cancers

Interleukin-6 (IL-6) is a pleiotropic cytokine with significant functions in the regulation of the immune system. As a potent pro-inflammatory cytokine, IL-6 plays a pivotal role in host defense against pathogens and acute stress. However, increased or deregulated expression of IL-6 significantly contributes to the pathogenesis of various human diseases. Numerous preclinical and clinical studies have revealed the pathological roles of the IL-6 pathway in inflammation, autoimmunity, and cancer. Based on the rich body of studies on biological activities of IL-6 and its pathological roles, therapeutic strategies targeting the IL-6 pathway are in development for cancers, inflammatory and autoimmune diseases. Several anti-IL-6/IL-6 receptor monoclonal antibodies developed for targeted therapy have demonstrated promising results in both preclinical studies and clinical trials. Tocilizumab, an anti-IL-6 receptor antibody, is effective in the treatment of various autoimmune and inflammatory conditions notably rheumatoid arthritis. It is the only IL-6 pathway targeting agent approved by the regulatory agencies for clinical use. Siltuximab, an anti-IL-6 antibody, has been shown to have potential benefits treating various human cancers either as a single agent or in combination with other chemotherapy drugs. Several other anti-IL-6-based therapies are also under clinical development for various diseases. IL-6 antagonism has been shown to be a potential therapy for these disorders refractory to conventional drugs. New strategies, such as combination of IL-6 blockade with inhibition of other signaling pathways, may further improve IL-6-targeted immunotherapy of human diseases.

Predictors of response and remission in a large cohort of rheumatoid arthritis patients treated with tocilizumab in clinical practice

OBJECTIVE

The objective of this study was to identify predictors of response and remission to tocilizumab (TCZ) in RA patients seen in daily routine clinical practice.

METHODS

The efficacy of TCZ was evaluated after 12 and 24 weeks of treatment by the European League Against Rheumatism (EULAR) response criteria. Regression analysis was performed to study the association between remission or EULAR response and the following characteristics: gender, age, current smokers, prior cardiovascular disease (CVD), 28-joint disease activity score (DAS28), CRP, RF or ACPA positivity, combination therapy with DMARDs and TCZ as the first biological therapy or after failure of at least one biological therapy.

RESULTS

In total, 204 patients were included with a mean DAS28 score of 5.14. EULAR response and remission were obtained in 86.1% and 40% of patients, respectively, at week 24. In multiple regression analysis, a high baseline CRP level [odds ratio (OR) 4.454 (95% CI 1.446, 13.726)] was significantly associated with EULAR response at week 24 and, inversely, age >55 years [OR 0.285 (95% CI 0.086, 0.950)] and prior CVD [OR 0.305 (95% CI 0.113, 0.825)] were significantly associated with lower EULAR response at week 24. Older age was also associated with less remission at week 24 [OR 0.948 (95% CI 0.920, 0.978)]. No additional effectiveness was found when TCZ was used in combination with a DMARD or when patients were naive to biological agents.

CONCLUSION

In daily practice we identified three predictors of a better response for TCZ therapy in RA: a younger age, a high baseline CRP level and no history of CVD.

Lead optimization of a 4-aminopyridine benzamide scaffold to identify potent, selective, and orally bioavailable TYK2 inhibitors

Herein we report our lead optimization effort to identify potent, selective, and orally bioavailable TYK2 inhibitors, starting with lead molecule 3. We used structure-based design to discover 2,6-dichloro-4-cyanophenyl and (1R,2R)-2-fluorocyclopropylamide modifications, each of which exhibited improved TYK2 potency and JAK1 and JAK2 selectivity relative to 3. Further optimization eventually led to compound 37 that showed good TYK2 enzyme and interleukin-12 (IL-12) cell potency, as well as acceptable cellular JAK1 and JAK2 selectivity and excellent oral exposure in mice. When tested in a mouse IL-12 PK/PD model, compound 37 showed statistically significant knockdown of cytokine interferon-γ (IFNγ), suggesting that selective inhibition of TYK2 kinase activity might be sufficient to block the IL-12 pathway in vivo.

Arid5a controls IL-6 mRNA stability, which contributes to elevation of IL-6 level in vivo

Posttranscriptional regulation of IL-6 has been largely uncharacterized, with the exception of the ribonuclease Regnase-1, which prevents autoimmunity by destabilizing IL-6 mRNA. Here, we identified AT-rich interactive domain-containing protein 5A (Arid5a) as a unique RNA binding protein, which stabilizes IL-6 but not TNF-α mRNA through binding to the 3' untranslated region of IL-6 mRNA. Arid5a was enhanced in macrophages in response to LPS, IL-1β, and IL-6. Arid5a deficiency inhibited elevation of IL-6 serum level in LPS-treated mice and suppressed IL-6 levels and the development of T(H)17 cells in experimental autoimmune encephalomyelitis. Importantly, Arid5a inhibited the destabilizing effect of Regnase-1 on IL-6 mRNA. These results indicate that Arid5a plays an important role in promotion of inflammatory processes and autoimmune diseases.

Retention of tocilizumab and anti-tumour necrosis factor drugs in the treatment of rheumatoid arthritis

OBJECTIVES

The retention of the anti-rheumatic agent tocilizumab (TCZ) has not been well documented in patients with rheumatoid arthritis (RA). We conducted an observational study to compare the retention of TCZ and anti-tumour necrosis factor (TNF) drugs in the treatment of patients with RA.

METHOD

We reviewed continuation rates and causes of discontinuation of biological agents (biologics) by assessing medical records of patients with RA who were administered biologics at our institute from September 1999 to April 2012, using the Osaka University Biologics for Rheumatic Diseases (BiRD) registry.

RESULTS

A total of 401 patients were included. TCZ, infliximab (IFX), etanercept (ETN), and adalimumab (ADA) were administered to 97, 103, 143, and 58 patients, respectively. There were some differences between the baseline characteristics of the groups. The median duration (range) of TCZ, IFX, ETN, and ADA administration was 2.5 (0.1-12.6), 1.9 (0.0-7.7), 2.9 (0.0-11.3), and 1.3 (0.0-3.4) years, respectively. Continuation rates for TCZ and ETN were significantly higher than those for IFX and ADA. Multivariate analyses showed that discontinuation due to lack or loss of efficacy was significantly less common in the TCZ group than in the other groups. Discontinuation due to overall adverse events was not significantly different between treatment groups.

CONCLUSION

TCZ and ETN show better retention than IFX or ADA in the treatment of RA.

The pathological and physiological roles of IL-6 amplifier activation

The NFκB-triggered positive feedback loop for IL-6 signaling in type 1 collagen+ non-immune cells (IL-6 amplifier) was first discovered to be a synergistic signal that is activated following IL-17A and IL-6 stimulation in type 1 collagen+ non-immune cells. Subsequent disease models have shown that it can also be stimulated by the simultaneous activation of NFκB and STAT3, functions as a local chemokine inducer, and acts as a mechanism for local inflammation, particularly chronic ones like rheumatoid arthritis and a multiple sclerosis. Moreover, we have recently shown that hyper activation of the IL-6 amplifier via regional neural activation establishes a gateway for immune cells including autoreactive T cells to pass the blood-brain barrier at dorsal vessels in 5(th) lumbar cord. Here we review how the IL-6 amplifier is activated by neural activation and the physiological relevance of the gateway to the central nervous system. Accumulating evidences continues to suggest that the IL-6 amplifier offers a potential molecular mechanism for the relationship between neural activation and the development of inflammatory diseases, which could establish a new interdisciplinary field that fuses neurology and immunology.