Emerging biologic therapies in rheumatoid arthritis: cell targets and cytokines

Anti-arthritic activity of ethanol extract of Claoxylon indicum on Freund's complete adjuvant-induced arthritis in mice

BACKGROUND

Claoxylon indicum Hassk. (Euphorbiaceae), named Diu Le Bang, have functions of dehumidification and relieving swelling pain, and is used as a folk medicine to treat Rheumatoid arthritis (RA), lumbocrural pain and foot edema in the south of China. The aim of the present study was to investigate the anti-arthritic activity of the ethanol extract of Claoxylon indicum (CIE) on mice with adjuvant induced joint arthritis.

METHODS

Adjuvant arthritis was induced in mice by subcutaneous injection of complete Freund's adjuvant into the plantar surface of right hind paw. Arthritis severity was evaluated by arthritic score, hind paws oedema and spleen index, and histological examinations. Serum samples were collected for determination of malondialdehyde (MDA) and alkaline phosphatase (ALP) levels. The expression of interleukin-1 beta (IL-1β) and tumor necrosis factor alpha (TNF-α) in the specimens of knee joints was determined by standard immunohistochemical techniques.

RESULTS

CIE administration (0.4 and 0.8 g/kg) suppressed the inflammatory responses in the joints of adjuvant-induced arthritis (AIA) mice, suggested by the modulatory effects on paw swelling, hyperplasia of lymphatic tissues and synovial membrane. It also decreased the levels of MDA and ALP in serum and downregulated the expression of IL-1β and TNF-α in the arthritic joints of AIA mice.

CONCLUSION

These results suggested that CIE possessed substantial anti-arthritic activity due to immumodepression and regulation of cytokines. CIE may be a potential candidate for the treatment of RA.

Mass cytometry as a platform for the discovery of cellular biomarkers to guide effective rheumatic disease therapy

The development of biomarkers for autoimmune diseases has been hampered by a lack of understanding of disease etiopathogenesis and of the mechanisms underlying the induction and maintenance of inflammation, which involves complex activation dynamics of diverse cell types. The heterogeneous nature and suboptimal clinical response to treatment observed in many autoimmune syndromes highlight the need to develop improved strategies to predict patient outcome to therapy and personalize patient care. Mass cytometry, using CyTOF®, is an advanced technology that facilitates multiparametric, phenotypic analysis of immune cells at single-cell resolution. In this review, we outline the capabilities of mass cytometry and illustrate the potential of this technology to enhance the discovery of cellular biomarkers for rheumatoid arthritis, a prototypical autoimmune disease.

The treatment strategies of autoimmune disease may need a different approach from conventional protocol: a review

Autoimmune disease (AD) is one of the emerging noncommunicable diseases. Remission is a possibility in AD, but current treatment strategies are not able to achieve this. We have well-established protocols for infections, oncology, metabolic diseases, and transplantation which are often used as models for the management of AD. Studies and observations suggest that in contrast to diseases used as a role model, AD has wide variability, different causative and pathogenic process, which is highly dynamic, making the current treatment strategies to fall short of expected complete remission. In this brief review, it is attempted to highlight the current understanding of AD and the probable gaps in the treatment strategies. Few hypothetical suggestions to modify the treatment protocols are presented.

Intraarticular gene delivery of CTLA4-FasL suppresses experimental arthritis

T lymphocytes are key inflammatory cells contributing significantly to the pathogenesis of Rheumatoid arthritis (RA). Biological treatments targeting T lymphocytes may provide an efficient approach for treatment of RA. CTLA4-FasL, a fusion product of extracellular domains of CTLA4 and FasL, integrating two inhibitory elements against T cells into one molecule, might be a desirable derivative of engineered soluble FasL or CTLA4 and have therapeutic potential in RA. The aim of this study was to investigate whether simultaneous induction of Fas-mediated apoptosis and blockade of co-stimulation signal by CTLA4-FasL gene delivery has a suppressive effect on adjuvant-induced arthritis (AIA) in Lewis rats. Recombinant adeno-associated virus (rAAV) vectors encoding rat CTLA4-FasL fusion gene (rAAV.CTLA4-FasL) or enhanced green fluorescent protein (rAAV.EGFP) were injected intraarticularly into both ankle joints after immunization. The ankles were monitored by measures of clinical, histological and inflammatory cytokines' changes. Treatment using rAAV.CTLA4-FasL resulted in a significant suppression of AIA compared with rAAV.EGFP control, as reflected in the mainly clinical signs including articular index, ankle joint thickness and paw swelling and typically histological characters of arthritic joints including synovial hyperplasia, inflammatory cells infiltration and cartilage degradation. Treatment with rAAV.CTLA4-FasL also significantly decreased the levels of key proinflammatory cytokines in AIA joints. Moreover, local productions of transgene mRNA and protein of CTLA4-FasL were found in injected joints without systemic distribution. Our results indicate that rAAV.CTLA4-FasL profoundly suppressed experimental model of RA, implicating the potential therapeutic applications for suppression of RA by local joint delivery of CTLA4-FasL.

Inhibitors of tumor necrosis factor-alpha for treatment ofpsoriatic patients

The article describes current concepts of the role of cytokines in the pathogenesis of inflammatory diseases. The authors describe the biological action of tumor necrosis factor-alpha and its soluble receptors on body cells. They also provide data on the role of tumor necrosis factor-alpha in the formation of skin and joint inflammatory affections at psoriasis. The authors substantiate treatment of medium to severe forms of psoriasis with biological gene-engineered anti-cytokine drugs, and provide and their comparative characteristics.

Biological agents targeting beyond TNF-alpha

Biological agents represent an important addition to the therapies for immuno-inflammatory conditions and have a great impact on the disease course and quality of life of these patients. However, recent reports of serious infections like tuberculosis, demyelinating and neurodegenerative diseases, pancytopenia, cardiovascular diseases, etc. after anti-TNF therapy raised questions on their safety. Hence, focus is shifted towards drugs targeting cytokine checkpoints in the inflammatory cascades beyond TNF-α. Existing therapeutic targets include the biological agents acting as antagonists of various inflammatory cytokines (Anakinra, Tocilizumab, Atlizumab) and modulators of CD80 or CD86-CD28 co-stimulatory signal (Abatacept), CD2 receptors on T-cells (Alefacept), CD11a, subunit of leukocyte function-associated antigen 1 (Efalizumab), vitronectin receptor and CD20 antigen on pre-B, immature and mature B cells (Rituximab). With the introduction of these novel molecules the future for immunomodulatory intervention in rheumatology, asthma, crohn's disease, septic shock etc. looks very promising. These novel therapeutic agents could truly give a new hope to the clinician to modify the disease and achieve tangible improvements in the lives of the patients.

The effects of infliximab therapy on the serum proteome of rheumatoid arthritis patients

Introduction

Although the clinical effects of infliximab therapy in rheumatoid arthritis have been documented extensively, the biological effects of this intervention continue to be defined. We sought to examine the impact of infliximab therapy on the serum proteome of rheumatoid arthritis patients by means of a mass spectrometry-based approach.

Methods

Sera from 10 patients with rheumatoid arthritis were obtained prior to and following 12 weeks of infliximab therapy using a standard clinical protocol. The sera were immunodepleted of the 12 highest abundance proteins, labeled by the iTRAQ (isobaric tagging for relative and absolute protein quantification) technique, and analyzed by mass spectrometry to identify proteomic changes associated with treatment.

Results

An average of 373 distinct proteins were identified per patient with greater than 95% confidence. In the 3 patients demonstrating the most robust clinical responses, changes of greater than 20% in the serum levels were observed in 39 proteins following treatment. The majority of these proteins were regulated directly or indirectly by tumour necrosis factor-alpha (TNF-α) and nuclear factor-kappa-B, with acute-phase proteins being uniformly down-regulated. A number of proteins, including members of the SERPIN family and S100A8, were down-regulated irrespective of clinical response.

Conclusions

The present study demonstrates that a robust clinical response to infliximab is associated with the down-regulation of a spectrum of serum proteins regulated by TNF-α, and provides a possible basis for defining the broader biological effects of the treatment in vivo.

Appreciating the Heterogeneity in Autoimmune Disease: Multiparameter Assessment of Intracellular Signaling Mechanisms

Autoimmune disease pathologies are multifactorial with complex interactive networks of cells and chemical messengers that initiate cascades of aberrant cellular activity. Rheumatoid arthritis (RA) is a chronic inflammatory disease that is characterized by systemic inflammation, destruction of the joints, and production of autoantibodies recognizing dozens of putative autoantigens. The presence of autoreactive T cells in individuals leads to pathological autoimmunity by activating additional cellular constituents to mediate inflammation and joint destruction. The etiology of RA is unknown, and knowledge is lacking of the molecular mechanisms underlying the production and subsequent regulation of autoreactive T cells and predicting patient responses to treatments. Biochemical investigations into mechanisms of the disease have relied on animal models that are helpful in dissecting elements of the disease but that are not necessarily reflective of human RA development. The study of multiple activated signaling pathways in complex populations of cells, such as peripheral blood, at the single-cell level has not previously been possible. This article describes how intracellular phosphoepitope staining methodology in conjunction with surface-cell immunophenotyping can be used to deconvolute cellular subsets and allow functional characterization of patient-derived material. Multiparameter flow cytometric analysis allows for small subpopulations-representing different cellular subsets and differentiation or activation states-to be discerned and simultaneously assessed for intracellular biochemical activities. This article also describes how single-cell signal network analysis can be used to stratify patients and may be useful for understanding mechanisms of disease progression, treatment resistance, and development of diagnostic indicators.

Immunological therapies for rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory arthritis of the synovial joints that causes loss of function and a shortened life expectancy. In the last 10 years there have been major advances in the treatment of RA, including more aggressive use of disease-modifying anti-rheumatic drugs and the development of immune therapies targeted to molecules and cells important in the immunopathogenesis of RA. Molecular messengers that travel between cells (cytokines) have been found to be of major importance. Blocking the cytokine tumour necrosis factor alpha (TNF-alpha) produces significant improvement in RA, ankylosing spondylitis, psoriatic arthritis, psoriasis and Crohn's disease. The use of cytokine blockers has shown the extent to which immune and inflammatory pathways are shared in a number of inflammatory diseases. There has also been an important proof of principle that blocking single cytokines can produce profound effects in inflammatory diseases.