Expression of TNFα membrane-bound receptors in the peripheral blood mononuclear cells (PMBC) in rheumatoid arthritis patients

Co-Expression of Membrane-Bound Tumor Necrosis Factor-Alpha Receptor Types 1 and 2 by Tumor Cell Lines

INTRODUCTION

Density and co-expression of tumor necrosis factor (TNF) receptors may vary among cell populations. However, the role and potential of these changes remain unclear. This study aimed to determine the density of expression and co-expression of TNFR1/2 and the dose-dependent effect of soluble TNF on these parameters.

METHODS

Epithelial-like (HEp-2, K-562, MCF-7, ZR-75/1) and lymphoblast-like (MOLT-4, HL-60, Raji, RPMI-8226, IM-9) cell lines were characterized for co-expression of TNFR1/2 using a modified flow cytometry protocol. The dose-dependent effects of rhTNF on TNF receptor expression in these lines were studied.

RESULTS

This study reports a protocol for the simultaneous quantitative evaluation of the of TNF receptor number and co-expression of membrane-bound TNFR1/2. Cells within one tumor cell line were found to differ regarding their expression of type 1 and 2 TNFα receptors; simultaneously, cells with all 4 variants of co-expression may be present in culture.

CONCLUSION

We demonstrated a dose-dependent effect of TNF on changes in the expression of TNFR1/2 by the percentage of positive cells and by the number of receptors, which may be used to control TNF-mediated processes in target cells.

Tumour necrosis factor signalling in health and disease

The master pro-inflammatory cytokine, tumour necrosis factor (TNF), has been shown to modulate multiple signalling pathways, with wide-ranging downstream effects. TNF plays a vital role in the typical immune response through the regulation of a number of pathways encompassing an immediate inflammatory reaction with significant innate immune involvement as well as cellular activation with subsequent proliferation and programmed cell death or necrosis. As might be expected with such a broad spectrum of cellular effects and complex signalling pathways, TNF has also been implicated in a number of disease states, such as rheumatoid arthritis, ankylosing spondylitis, and Crohn’s disease. Since the time of its discovery over 40 years ago, TNF ligand and its receptors, TNF receptor (TNFR) 1 and 2, have been categorised into two complementary superfamilies, namely TNF (TNFSF) and TNFR (TNFRSF), and 19 ligands and 29 receptors have been identified to date. There have been significant advances in our understanding of TNF signalling pathways in the last decade, and this short review aims to elucidate some of the most recent advances involving TNF signalling in health and disease.

Curculigoside exerts significant anti‑arthritic effects in vivo and in vitro via regulation of the JAK/STAT/NF‑κB signaling pathway

The present study aimed to investigate the anti-arthritic effects of curculigoside isolated from the rhizome of Curculigo orchioides Gaertn in vivo and in vitro, as well as to determine the potential underlying mechanisms. A rat model of arthritis was induced with type II collagen. Arthritic rats were treated with curculigoside (50 mg/kg) and blood samples were collected to determine serum levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, IL-10, IL-12 and IL-17A. Furthermore, indices of the thymus and spleen were determined. The anti-proliferative effects of curculigoside were detected with Cell Counting kit-8 assays in rheumatoid arthritis-derived fibroblast-like synoviocyte MH7A cells. In addition, expression levels of Janus kinase (JAK)1, JAK3, signal transducer and activator of transcription (STAT)3, nuclear factor (NF)-κB p65 and its inhibitor (IκB) were determined by western blotting. The results revealed that curculigoside inhibited paw swelling and arthritis scores in type II collagen-induced arthritic (CIA) rats. Additionally, curculigoside decreased serum levels of TNF-α, IL-1β, IL-6, IL-10, IL-12 and IL-17A in CIA rats. Curculigoside also significantly inhibited MH7A cell proliferation in a time and concentration-dependent manner. Furthermore, treatment downregulated the expression of JAK1, JAK3 and STAT3, and upregulated cytosolic nuclear factor (NF)-κB p65 and IκB. In conclusion, the results of the present study indicated that curculigoside exhibited significant anti-arthritic effects in vivo and in vitro, and the molecular mechanism may be associated with the JAK/STAT/NF-κB signaling pathway.

Expression Density of Receptors as a Potent Regulator of Cell Function and Property in Health and Pathology

The expression of cytokine receptors has a crucial role in many cellular processes. Recent studies reported that changes of receptor expression could control the action of mediators on target cells. The initiation of different signaling pathways and, therefore, specific effects on cells, depends on certain components forming the cytokine-receptor complex. These mechanisms control the immune response and affect both the course of diseases (oncological, autoimmune, inflammatory) and the effectiveness of therapy. This review describes the potential of immune mediator receptors to regulate the efficiency of cytokine activity during pathologic processes and ensure the variability of their biological effects. Our aim was to investigate the spectrum of potential roles of changes in mediator receptor expression for main classes of pathologies. For all major types of immune mediators (cytokines, interleukins, chemokines, growth factors, and tumor necrosis factors), it has been shown that changes in their receptor expression are associated with impaired functioning of the organism in chronic diseases.

Therapeutic effects of Caragana pruinosa Kom. roots extract on type II collagen-induced arthritis in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Caragana pruinosa Kom. is a deciduous shrub belonging to the genus of Caragana (Leguminosae), and Caragana plants exhibit a wide range of interesting pharmacological properties including anti-inflammatory, analgesic, and anti-arthritis activity, etc.

AIM OF THE STUDY

This study was aimed to investigate the anti-arthritic effect of 80% EtOH extract from the roots of C. pruinosa (ERCP) on arthritis and explore the potential pharmacological mechanism.

MATERIALS AND METHODS

After collagen induced arthritis (CIA) were established in rats, the animals were orally administered with ERCP (130, 260 and 520mg/kg) for 30 days. During the treatment, the rats' body weights, arthritis indices and paw volumes were measured every 5 days. Subsequently, rats' blood samples were collected to determine TNF-α, IL-1β, IL-6, IL-10, and C-reactive protein (CRP) contents in serum. Then, rats were sacrificed and the hind paws and knee joints were collected for histopathological examination.

RESULTS

Our results indicated that ERCP significantly suppressed the inflammatory reactions and destructions in joints and synovial tissues. ERCP inhibited the paw swelling and arthritis index in CIA rats. Additionally, it decreased the levels of pro-inflammatory cytokines (TNF-α, IL-1β and IL-6) and CRP, whereas increased that of IL-10.

CONCLUSION

Our results suggested ERCP has significant anti-arthritic effect on CIA rats, and the pharmacological mechanisms are related to the down-regulation of TNF-α, IL-1β, IL-6 and CRP and the up-regulation of IL-10.

TNFα in the regulation of Treg and Th17 cells in rheumatoid arthritis and other autoimmune inflammatory diseases

TNFα is a principal pro-inflammatory cytokine vital for immunity to infections. However, its excessive production is involved in chronic inflammation and disease pathology in autoimmune diseases. Evidence for its pathogenic role is validated by the fact that its neutralisation by therapeutic agents in vivo is beneficial in ameliorating disease and controlling symptoms. Paradoxically, however, treatment with TNFα inhibitors can either have no clinical effects, or even exacerbate disease in some patients. The explanation for such contradictory outcomes may lay in how and which downstream signalling pathways are activated and drive disease. TNFα causes its effects by binding to either or both of two membrane-bound receptors, TNFR1 and TNFR2. Engagement of the receptors can induce cell death or cell proliferation. T cells both produce and respond to TNFα and depending on whether the cytokine is membrane-bound or soluble and the level of expression of its two receptors, the biological outcome can be distinct. In addition, polymorphisms in genes encoding TNFα and T cell signalling proteins can significantly impact the outcome of TNFα receptor engagement. Early studies revealed that effector T cells in patients with rheumatoid arthritis (RA) are hyporesponsive due to chronic exposure to TNFα. However, recent evidence indicates that the relationship between TNFα and T cell responses is complex and, at times, can be paradoxical. In addition, there is controversy as to the specific effects of TNFα on different T cell subsets. This review will summarise knowledge on how TNFα modulates T cell responses and the effect of engaging either of its two receptors. Furthermore, we discuss how such interactions can dictate the outcome of treatment with TNFα inhibitors.

Interleukin-6 (IL-6) Receptor Antagonist Protects Against Rheumatoid Arthritis

Background

The aim of this study was to investigate the protective effect of interleukin-6 (IL-6) receptor antagonist tocilizumab (TCZ) on rheumatoid arthritis (RA) and its related mechanism.

Material/Methods

Thirty RA patients receiving long-term methotrexate therapy at moderate and severe active stages were selected and treated with TCZ 8 mg/kg/time iv gtt intravenously guttae every 4 weeks. Peripheral blood was extracted before and 24 weeks after TCZ treatment. Peripheral blood mononuclear cells (PBMC) were collected by density gradient centrifugation. Flow cytometry was used to detect the ratio of CD4 naïve T cells and CD4 memory T cells, Th17 cells, and Treg cells in PBMC. DAS28 score, CRP, RF, and CCP levels in patients were evaluated.

Results

Compared with before treatment, IL-6 receptor antagonist TCZ significantly improved patients’ condition, including DAS28 score, CRP, RF, and CCP levels (P<0.01). Furthermore, TCZ obviously upregulated CD4 naïve T cells proportion and decreased CD4 memory T cells ratio (P<0.01). TCZ also markedly reduced the proportion of Th17 cells and increased the proportion of Treg cells (P<0.01).

Conclusions

TCZ can treat RA patients through regulating the ratio of CD4 naïve T cells, CD4 memory T cells, Th17 cells, and Treg cells in PBMC.

Expression density of receptors to IL-1β in atopic dermatitis

Interleukin 1 (IL-1 β) and the system for regulation of its biological effects play an important role in the development and behavior of inflammatory processes in atopic dermatitis. Notably, cells that are actively involved in the pathological process have altered expression of cytokine receptors. However, standard evaluation of cells by flow cytometry measures only the percentage of cells expressing the appropriate marker, which is not enough for a full assessment of these changes. The aim of this study was to investigate changes in the expression of IL-1β cytokine receptors in patients with atopic dermatitis by both percentage of cells with receptors in various subsets and the absolute number of membrane-bound receptors themselves. It was found that an increase or decrease in the percentage of cells expressing the receptors in subsets of immune cells in patients with atopic dermatitis was not associated with a change in the number of receptors on the cell surface. Moreover, the changes in the percentage of cells and the number of receptors may occur in different directions, as shown for IL-1R2 expression on B cells and IL-1R1 expression for monocytes. Changes in the parameters of IL-1β receptor expressions are associated with disease severity index SCORAD in atopic dermatitis. These findings underline the importance of studying the density of cytokine receptor expression in the pathology.