**4. Medical treatments for RA**

160 Rheumatoid Arthritis – Etiology, Consequences and Co-Morbidities

both abundantly expressed in the IL-1-induced MH7A cells (57.8- and 12.6-fold increases, respectively). IL-12 is a heterodimer expressed in RA synovial tissue (Morita et al., 1998); dendritic cells and macrophages produce IL-12 within minutes of activation, and it plays a central role in the development of Th1 responses (Hunter, 2005). The biological functions of these cells are not yet fully understood, but they are known to play a role in the differentiation and proliferation of T cells of the Th1 phenotype. Th1 responses in turn are deemed to be of particular importance in inflammatory arthritis, including RA. This induction of IL-12p70 by IL-1 in MH7A cells may be the first *in vitro* evidence of IL-12 expression in RA. This is noteworthy, because Connell & McInnes (Connell & McInnes, 2006) suggested in their review that IL-12 likely contributes to the pathology of inflammatory joint disease. If this is the case, it

**Fold Protein Name Non-treated IL-1b-treated** 

57.8 IL-12 p70 0.01 *nd* 0.58 3384 ± 104 12.6 IL-8 0.01 *nd* 0.13 737 ± 104 2.6 IL-16 0.01 49 ± 99 0.03 162 ± 54

3.7 MMP-10 0.01 *nd* 0.04 219 ± 44 2.3 MMP-11 (Stromelysin-3) 0.01 *nd* 0.02 134 ± 26

0.3 TIMP-1 0.72 3270 ± 1051 0.24 1395 ± 129 0.4 TIMP-3 0.28 1296 ± 65 0.11 643 ± 296

expression levels of 507 proteins in culture medium conditioned by MH7A cells. The cell were cultured for 16 h and then treated with IL-1 (0.1 U/ml) for 3 h. The cultured medium from five wells was then combined and dialyzed against PBS (pH 8.0), and an internal control protein was added to the 400 µl of dialyzed sample medium. The procedure used for biotin labeling, blocking and incubation of the antibody array, as well as fluorescence detection were carried out according to the operating manual from RayBiotech. The images were captured using an Axon GenePix laser scanner. Biotinylation of the internal control protein yielded a positive control signals that was used to identify the orientation of the results and help normalize them for comparison of those from the untreated and IL-1-treated MH7A

On the other hand, the levels of two MMP family enzymes, MMP-10, and MMP-11 were upregulated by IL-1, while the levels of TIMP-1 and -3 were downregulated. As the overall MMP activity reflects a balance between the amount of MMPs and TIMPs present, the reduction in TIMP-1 and TIMP-3 levels seen in MH7A cells would be expected to shift the balance in favor of increased MMP activity. Taken together, these data suggest that IL-1 elicits a series of responses in the synovial fluid, leading to the pathology seen in RA, including enhanced expression of inflammatory cytokines and enzymes, and a reduction in

RayBio biotin label-based human antibody array I (RayBiotech, Inc.) was used to measure the

**Normalized Raw (n=3) Normalized Raw (n=3)** 

may represent a potentially useful therapeutic target.

cell arrays. Values below 0.01 were set to 0.001.

the ability to protect against the destruction of the tissue ECM.

Table 1. IL-1-induced protein.

**ILs** 

 **MMPs** 

 **TIMPs**  Several disease-modifying anti-rheumatic drugs (DMARDs) have been used to control the progression of RA. While the majority of these drugs act as immunomodulatory agents, some also act by inhibiting cytokines and endothelial cell proliferation (Cozzolino et al., 1993, Volin et al., 1999). Newly developed biological response modifiers (biologics) offer even more hope, having a greater potential to suppress disease activity, and improve the quality of life of RA patients.
