Arthritis & Rheumatism, Volume 63,
November 2011 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Chicago, Illinois November 4-9, 2011.


Extracellular 14-3-3: An Early Rheumatoid Arthritis Pathogenic Factor.

Marotta1,  Anthony, Bykerk2,  Vivian, Siminovitch3,  Katherine A., Boers4,  Maarten, Landewe5,  Robert, van der Heijde6,  Désirée, Tak7,  Paul-Peter

Augurex Life Sciences Corp, North Vancouver, BC
University of Alberta, Edmonton, AB
Brigham & Women's Hospital, Boston, MA
Mount Sinai Hospital, Toronto, ON
VU University Medical Center, Amsterdam, Netherlands
Academic Medical Center, Amsterdam, Netherlands
Department of Rheumatology, Leiden University Medical Center, Leiden, Netherlands
Professor of Medicine/ Director, Division of Clinical Immunology and Rheumatology, Amsterdam, Netherlands
Stanford University Medical Center, Palo Alto, CA
Department of Medicine, Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, MA

Background/Purpose:

14-3-3 proteins are ubiquitously expressed intracellular chaperonins. We previously showed that the h isoform is 1) uniquely expressed in the synovial fluid and serum of patients with inflammatory arthritis 2) differentially expressed in established rheumatoid arthritis (RA) and 3) a novel extracellular mediator that may contribute to the disease process. This study examines 14-3-3h serum levels and its pathophysiological role in early disease.

Methods:

Serum 14-3-3h was measured in 37 DMARD-naïve early RA patients, 25 from the Toronto Early Arthritis Cohort (TEACH) and 12 from the intensified-COBRA cohort, and 50 osteoarthritis (OA) controls using an investigational-grade 14-3-3h ELISA. 2-tailed t-tests and Mann-Whitney u-tests were run to compare group differences in serum concentrations. An ROC curve was generated and sero-positivity rates of 14-3-3h, rheumatoid factor (RF) and anti-citrullinated cyclic peptide (anti-CCP) were evaluated. To examine the effects of 14-3-3h on intracellular signalling in monocytes, THP-1 monocytic cells were stimulated with 12.5ng/ml of recombinant human 14-3-3h (0–30min) and activation of the MAPK signalling cascades (ERK, JNK/SAPK and p38) were assessed by immunoblot analysis using phosphospecific antibodies. The mRNA levels of IL-1b, IL-8, CCL2/MCP-1 and CCL4/MIP1- b following 18h incubation with a dose range of 0.10 to 100ng/ml of recombinant human 14-3-3h or vehicle were assessed by RT-PCR. Densitometry was used to measure % change with stimulation above control.

Results:

Mean and median 14-3-3h serum concentrations in RA patients [TEACH (3.13 & 0.63ng/ml) and i-COBRA (5.90 & 1.43ng/ml)] were significantly higher than in OA controls (0.32 & < 0.20ng/ml), p-values <0.0006 and <0.0001, respectively. The corresponding areas under the ROC curve were 0.72 (95%CI 0.58–0.86) and 0.87 (95%CI 0.72–1.00) for TEACH and i-COBRA RA patients versus OA. 14-3-3h, RF and anti-CCP positivity were 60%, 32% and 44% in TEACH and 82%, 82% and 82% in i-COBRA. 72% of TEACH and 100% of i-COBRA RA patients were positive for any one of the three markers. Stimulation of THP-1 cells with 14-3-3h activated ERK and JNK/SAPK by 227% and 87% above control at 5 and 2 min, respectively. No activation of p38MAPK was observed at any of the time points. 14-3-3h was associated with potent induction of transcripts of early pro-inflammatory factors, with IL-8 (47% increase at 0.1ng/ml) and MIP-1b (53% increase at 0.25ng/ml) being the most sensitive followed by MCP-1 (44% increase at 0.5ng/ml) and IL-1b (49% increase at 5ng/ml).

Conclusion:

14-3-3h is differentially expressed in the serum of patients with early RA compared to OA controls and is a novel factor that may contribute to pathological processes involved in early disease. 14-3-3h serum expression when combined with standard serological RA tests may mark early RA.

To cite this abstract, please use the following information:
Marotta, Anthony, Bykerk, Vivian, Siminovitch, Katherine A., Boers, Maarten, Landewe, Robert, van der Heijde, Désirée, et al; Extracellular 14-3-3: An Early Rheumatoid Arthritis Pathogenic Factor. [abstract]. Arthritis Rheum 2011;63 Suppl 10 :378
DOI:

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