Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.


An Endothelium-Specific NF-kappaB Inhibitor Ameliorates Inflammatory Joint Diseases.

Sehnert4,  Bettina, Burkhardt2,  Harald, Nimmerjahn5,  Falk, Wessels1,  Johannes, Machnik5,  Agnes, Vestweber6,  Dietmar, Zwerina5,  Jochen

Georg-August-University of Göttingen
Johann Wolfgang Goethe University Frankfurt am Main
Technical University of Braunschweig
University of Erlangen-Nürnberg, Erlangen, Germany
University of Erlangen-Nürnberg
University of Münster

Background:

Therapeutical strategies that systemically block nuclear transcription factor-kappaB (NF-kappaB)-signalling may cause serious side effects due to the important role of NF-kappaB in a variety of homeostatic regulatory pathways, for instance in the central nervous system, the liver and the immune system. NF-kappaB is a key player in inflammatory disorders such as rheumatoid arthritis. Activation induces the expression of multiple mediators involved in the initiation and perpetuation of inflammatory processes. We developed a novel class of NF-kappaB inhibitors, designated as ligand-sneaking construct (LSC), that interfere with the NF-kappaB signalling pathway selectively in endothelial cells. We have choosen this cell population, because of its essential role in the extravasation of leukocytes in inflammation.

Methods:

The LSC is a multimodular recombinant protein that consists of three domains: 1) an oligopeptide specifically binding the cytokine-activated endothelium 2) the translocation domain of pseudomonas exotoxin A (ETA II) that facilitates the endosomal release of the construct into the cytosol and 3) the NEMO-binding peptide (NF-kappaB inhibiting effector domain) (5). The effectiveness of this E-selectin specific construct (LSC1) on NF-kappaB activation was analysed in vitro by an NF-kappaB-luciferase reporter gene assay and EMSA. In vivo binding of LSC1 to the cytokine-activated endothelium was proven by using the Olympus OV100 whole-mouse imaging system. The therapeutic effect of LSC1 in vivo was investigated in the antigen-induced arthritis and the KBN serum transfer model.

Results:

E-selectin mediated internalization of LSC1 inhibited the transcriptional NF-kappaB activity in E-selectin expressing cells (CHO_E cells). Additionally, EMSA indicated a reduced nuclear translocation of NF-kappaB upon cytokine activation in LSC1-pretreated CHO_E cells. In vivo imaging emphasized specific LSC1 binding to the activated endothelium. By whole mount immunofluorescence microscopy of tissue specimens derived from cytokine-activated mouse skin, nuclear form of NF-kappaB p65 was strongly suppressed in mice pretreated with LSC1 but not in control mice that had received the MutNBP2 construct. In the mouse model of antigen-induced arthritis, we observed a reduced joint swelling after LSC1 treatment. Moreover, LSC1 leads to an amelioration of inflammatory joint disease induced by anti-glucose 6 phosphoisomerase (anti-G6PI) mouse serum. Histological studies confirmed the clinical data.

Conclusions:

We presented for the first time an endothelium specific NF-kappaB inhibitor that shows therapeutic potential to treat inflammatory joint diseases in different mouse models of arthritis. This proof of concept study can be employed for targeting other cell types and to interfere with distinct signalling pathways.

To cite this abstract, please use the following information:
Sehnert, Bettina, Burkhardt, Harald, Nimmerjahn, Falk, Wessels, Johannes, Machnik, Agnes, Vestweber, Dietmar, et al; An Endothelium-Specific NF-kappaB Inhibitor Ameliorates Inflammatory Joint Diseases. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :2234
DOI: 10.1002/art.29997

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