Sonya Abraham

Dexamethasone Causes Sustained Expression of Mitogen-Activated Protein Kinase (MAPK) Phosphatase 1 and Phosphatase-Mediated Inhibition of MAPK p38

ABSTRACT The stress-activated protein kinase p38 stabilizes a number of mRNAs encoding inflammatory mediators, such as cyclooxygenase 2 (Cox-2). In HeLa cells the anti-inflammatory glucocorticoid dexamethasone destabilizes Cox-2 mRNA by inhibiting p38 function. Here we demonstrate that this effect is phosphatase dependent. Furthermore, in HeLa cells dexamethasone induced the sustained expression of mitogen-activated protein kinase phosphatase 1 (MKP-1), a potent inhibitor of p38 function. The inhibition of p38 and the induction of MKP-1 by dexamethasone occurred with similar dose dependence and kinetics. No other known p38 phosphatases were induced by dexamethasone, and other cell types which failed to express MKP-1 also failed to inhibit p38 in response to dexamethasone. The proinflammatory cytokine interleukin 1 (IL-1) induced MKP-1 expression in a p38-dependent manner and acted synergistically with dexamethasone to induce MKP-1 expression. In HeLa cells treated with IL-1 or IL-1 and dexamethasone, the dynamics of p38 activation mirrored the expression of MKP-1. These observations suggest that MKP-1 participates in a negative-feedback loop which regulates p38 function and that dexamethasone may inhibit proinflammatory gene expression in part by inducing MKP-1 expression.

Antiinflammatory effects of dexamethasone are partly dependent on induction of dual specificity phosphatase 1

Glucocorticoids (GCs), which are used in the treatment of immune-mediated inflammatory diseases, inhibit the expression of many inflammatory mediators. They can also induce the expression of dual specificity phosphatase 1 (DUSP1; otherwise known as mitogen-activated protein kinase [MAPK] phosphatase 1), which dephosphorylates and inactivates MAPKs. We investigated the role of DUSP1 in the antiinflammatory action of the GC dexamethasone (Dex). Dex-mediated inhibition of c-Jun N-terminal kinase and p38 MAPK was abrogated in DUSP1−/− mouse macrophages. Dex-mediated suppression of several proinflammatory genes (including tumor necrosis factor, cyclooxygenase 2, and interleukin 1α and 1β) was impaired in DUSP1−/− mouse macrophages, whereas other proinflammatory genes were inhibited by Dex in a DUSP1-independent manner. In vivo antiinflammatory effects of Dex on zymosan-induced inflammation were impaired in DUSP1−/− mice. Therefore, the expression of DUSP1 is required for the inhibition of proinflammatory signaling pathways by Dex in mouse macrophages. Furthermore, DUSP1 contributes to the antiinflammatory effects of Dex in vitro and in vivo.

Efficacy and safety of apremilast, an oral phosphodiesterase 4 inhibitor, in ankylosing spondylitis

Objectives To evaluate the efficacy and safety of an oral phosphodiesterase 4 inhibitor, apremilast, in treatment of ankylosing spondylitis (AS) by monitoring symptoms and signs in a pilot study including exploratory investigation of effects of PDE4 inhibition on blood biomarkers of bone biology. Methods In this double-blind, placebo-controlled, single-centre, Phase II study, patients with symptomatic AS with active disease on MRI were randomised to apremilast 30 mg BID or placebo over 12 weeks. Bath Indices were monitored serially. Patients were followed for 4 weeks after stopping medication. Bone biomarkers were assessed at baseline and day 85. Results 38 subjects were randomised and 36 subjects completed the study. Although the primary end-point (change in BASDAI at week 12) was not met, apremilast was associated with numerically greater improvement from baseline for all clinical assessments compared with placebo with mean change in BASDAI (−1.59±1.48 vs −0.77±1.47), BASFI (−1.74±1.91 vs −0.28±1.61) and BASMI (−0.51±1.02 vs −0.21±0.67); however, differences did not achieve statistical significance. The clinical indices returned to baseline values by 4 weeks after cessation of apremilast. Six apremilast patients (35.3%) vs 3 placebo (15.8%) achieved ASAS20 responses (p=0.25). There were statistically significant decreases in serum RANKL and RANKL:osteoprotegrin ratio and plasma sclerostin but no significant changes in serum DKK-1, bone alkaline phosphatase, TRAP5b, MMP3, osteoprotegrin, or osteocalcin. Conclusions Although a small pilot study, these results suggest that apremilast may be effective and well tolerated in AS and modulates biomarkers of bone biology. These data support further research of apremilast in axial inflammation.

Incomplete response of inflammatory arthritis to TNFα blockade is associated with the Th17 pathway

Objectives To establish if changes in Th1/Th17 cell populations previously reported in experimental arthritis occur in patients with rheumatoid arthritis (RA) treated with anti-tumour necrosis factor α (TNFα) agents, and whether the therapeutic response to anti-TNFα is compromised in patients and mice because of elevated Th17/IL-17 levels. Finally, to assess the efficacy of combined blockade of anti-TNFα and anti-IL-17 in experimental arthritis. Methods A longitudinal study of two independent cohorts (cohort 1, n=24; cohort 2, n=19) of patients with RA treated with anti-TNFα biological agents was carried out to assess their Th17/IL-17 levels before and after the start of anti-TNFα therapy. IL-12/23p40 production was assessed in plasma Peripheral blood lymphocytes (PBLs) and monocytes. Mice with collagen-induced arthritis (CIA) were treated with anti-TNFα alone, anti-IL17 alone or a combination of the two. Efficacy of treatment and response was assessed from changes in Disease Activity Score 28–erythrocyte sedimentation rate scores in patients, and in clinical scores and histological analysis in CIA. Results Significant increases in circulating Th17 cells were observed in patients after anti-TNFα therapy and this was accompanied by increased production of IL-12/23p40. There was an inverse relationship between baseline Th17 levels and the subsequent response of patients with RA to anti-TNFα therapy. In addition, PBLs from non-responder patients showed evidence of increased IL-17 production. Similarly, in anti-TNFα-treated mice, there was a strong correlation between IL-17 production and clinical score. Finally combined blockade of TNFα and IL-17 in CIA was more effective than monotherapy, particularly with respect to the duration of the therapeutic effect. Conclusions These findings, which need to be confirmed in a larger cohort, suggest that a Th17-targeted therapeutic approach may be useful for anti-TNFα non-responder patients or as an adjunct to anti-TNFα therapy, provided that safety concerns can be addressed.

Dual‐specificity phosphatase 1–null mice exhibit spontaneous osteolytic disease and enhanced inflammatory osteolysis in experimental arthritis

OBJECTIVE Bone formation and destruction are usually tightly linked; however, in disorders such as rheumatoid arthritis, periodontal disease, and osteoporosis, elevated osteoclast activity leads to bone destruction. Osteoclast formation and activation are controlled by many signaling pathways, including p38 MAPK. Dual-specificity phosphatase 1 (DUSP-1) is a factor involved in the negative regulation of p38 MAPK. The purpose of this study was to examine the effect of Dusp1 deficiency on bone destruction. METHODS Penetrance, onset, and severity of collagen-induced arthritis were recorded in DUSP-1+/+ and DUSP-1-/- mice. Bone destruction was assessed by histologic and micro-computed tomographic examination of the joints. The in vitro formation and activation of osteoclasts from DUSP-1+/+ and DUSP-1-/- precursors were assessed in the absence or presence of tumor necrosis factor (TNF). RESULTS The formation and activation of osteoclasts in vitro in the presence of TNF were enhanced by Dusp1 gene disruption. DUSP-1-/- mice exhibited higher penetrance, earlier onset, and increased severity of experimental arthritis, accompanied by greater numbers of osteoclasts in inflamed joints and more extensive loss of bone. A DUSP-1-/- mouse colony of mixed genetic background also demonstrated striking spontaneous osteolytic destruction of distal phalanges. CONCLUSION DUSP-1 is a critical regulator of osteoclast activity and limits bone destruction in an experimental model of rheumatoid arthritis. Defects in the expression or activity of DUSP1 in humans may correlate with a propensity to develop osteolytic lesions in arthritis.

Anti-tumour necrosis factor treatment increases circulating T helper type 17 cells similarly in different types of inflammatory arthritis

We investigated changes in circulating T helper type 17 (Th17) cells following anti‐tumour necrosis factor (TNF) in rheumatoid arthritis (RA), ankylosing spondylitis (AS) and psoriatic arthritis (PsA) patients. Peripheral blood mononuclear cells (PBMC) were isolated from 25 RA, 15 AS and eight PsA patients at baseline 4 and 12 weeks after treatment, and Th17 cell frequencies were analysed using interleukin (IL)‐17 enzyme‐linked immunospot (ELISPOT) and flow cytometry. A significant increase in IL‐17‐producing cells was observed by ELISPOT in RA and AS patients at 12 weeks. Flow cytometry confirmed significant increases in CD4+IL‐17+ cells at 12 weeks in RA and AS and 4 weeks in PsA patients. Anti‐TNF treatment increases circulating Th17 cells in three different diseases.

Quantitative power Doppler ultrasound measures of peripheral joint synovitis in poor prognosis early rheumatoid arthritis predict radiographic progression

OBJECTIVE To assess the value of quantitative vascular imaging by power Doppler US (PDUS) as a tool that can be used to stratify patient risk of joint damage in early seropositive RA while still biologic naive but on synthetic DMARD treatment. METHODS Eighty-five patients with seropositive RA of <3 years duration had clinical, laboratory and imaging assessments at 0 and 12 months. Imaging assessments consisted of radiographs of the hands and feet, two-dimensional (2D) high-frequency and PDUS imaging of 10 MCP joints that were scored for erosions and vascularity and three-dimensional (3D) PDUS of MCP joints and wrists that were scored for vascularity. RESULTS Severe deterioration on radiographs and ultrasonography was seen in 45 and 28% of patients, respectively. The 3D power Doppler volume and 2D vascularity scores were the most useful US predictors of deterioration. These variables were modelled in two equations that estimate structural damage over 12 months. The equations had a sensitivity of 63.2% and specificity of 80.9% for predicting radiographic structural damage and a sensitivity of 54.2% and specificity of 96.7% for predicting structural damage on ultrasonography. CONCLUSION In seropositive early RA, quantitative vascular imaging by PDUS has clinical utility in predicting which patients will derive benefit from early use of biologic therapy.

The exaggerated inflammatory response in Behçet's syndrome: identification of dysfunctional post-transcriptional regulation of the IFN-γ/CXCL10 IP-10 pathway

The mechanisms underlying the exaggerated inflammatory response in Behçets syndrome (BS) remain poorly understood. We investigated the response of CD14+ blood monocytes to interferon (IFN)‐γ, focusing on the chemokine CXCL10. Chemokine synthesis and release were analysed at a protein and mRNA level following stimulation with IFN‐γ. Findings in BS patients were compared with 25 healthy controls (HC), 15 rheumatoid arthritis (RA) and 15 systemic lupus erythematosus (SLE) disease control patients. BS monocytes produced significantly more CXCL10 protein than HC monocytes from 2 h following IFN‐γ stimulation, despite equivalent quantities of mRNA, suggesting more efficient translation. This was significantly more pronounced in BS with high disease activity and in those with ocular and neurological clinical manifestations. The imbalance between CXCL10 protein and mRNA expression was not observed in either RA or SLE patients, and was not seen with other chemokines studied (CXCL9, CXCL11 and CCL2). Furthermore, BS monocytes treated with an alternative stimulant (LPS) did not show abnormal tumour necrosis factor (TNF)‐α release. Sucrose density gradients to segregate monocyte CXCL10 mRNA into free RNA or polysome‐associated RNA showed equal proportions in BS and HC samples, suggesting that the difference between BS and HC may be due to reduced negative control of CXCL10 translation in BS at a post‐initiation level. We conclude that BS monocytes have dysfunctional post‐transcriptional regulation of CXCL10 mRNA, resulting in over‐expression of CXCL10 protein upon IFN‐γ stimulation. As CXCL10 is a chemokine that recruits mononuclear cells, this abnormality may contribute to the exaggerated inflammatory responses that characterizes BS.

Respiratory symptoms in a patient on anti-tumour necrosis factor therapy; beware the negative enzyme linked immuno-spot (ELISpot) in suspected mycobacterial disease

Mycobaterium tuberculosis (MTB) accounts for significant morbidity and mortality worldwide. Non-tuberculous mycobacteria (NTM) species, usually considered benign contaminants, are increasingly recognized to be associated with pulmonary disease in immuno-compromised hosts. The tuberculin skin test (TST) is of limited benefit in immuno-supressed individuals who often fail to mount a delayed type hypersensitivity reaction. In such patients, the ELISpot assay is considered a more robust method of diagnosing tuberculosis. We present a case which illustrates that ELISpot can be negative in mycobacterial disease. A 51 year old Jamaican housekeeper, living in the UK for the past 45 years, presented with a 5-month history of a productive cough, shortness of breath and fatigue. She had a 10 year history of sero-positive rheumatoid arthritis which was well controlled with methotrexate and etanercept, an anti-tumour necrosis factor (TNF) biologic. She had …

Good practice in shared care for inflammatory arthritis

#### Clinical Question How should we manage disease-modifying antirheumatic drugs (DMARDs) in primary care when used as part of a shared-care arrangement in inflammatory arthritis? Inflammatory arthritis such as rheumatoid and psoriatic arthritis are chronic diseases requiring long-term management. The overall goal of treatment is to achieve remission or sustained low disease activity.1 The majority of patients are managed effectively using disease-modifying antirheumatic drugs (DMARDs). Traditionally, patients have been managed in secondary care by planned consultation with a rheumatologist every 3–6 months. This system of follow-up accounts for >75% of a rheumatologist’s workload2 and evidence has shown that up to 45% of routine consultations are undertaken without demonstrated patient need.3 Projected future shortages of specialist physicians including rheumatologists mean this arrangement may be untenable in the near future.3 Greater emphasis has therefore been placed on managing patients with stable inflammatory arthritis within the community using shared-care arrangements. Innovations within primary care have developed the role of specialist nurse practitioners and interface teams responsible for the continued monitoring of DMARDs. Shared care is defined as: ‘… the joint participation of GPs and specialists in the planned delivery of care for patients with a chronic condition, informed by an enhanced information exchange, over and above the routine discharge/referral letters.’ 4 This model has been used successfully for >10 years in chronic conditions including asthma and diabetes. Studies have consistently demonstrated that versions of shared care are not inferior to traditional follow-up in controlling disease activity in patients with inflammatory arthritis.3,5,6 Furthermore, symptom control facilitated by shared care is likely to be more cost-effective than treatment delivered in secondary care in 60–90% of cases.7 In the UK it is becoming common to manage patients with stable inflammatory arthritis within primary care using a shared-care arrangement, once …