Chemokine receptor expression and in vivo signaling pathways in the joints of rats with adjuvant‐induced arthritis

Abstract

Objective. This study was undertaken to characterize the role of CC chemokines and their receptors in rat adjuvant-induced arthritis (AIA), a model for rheumatoid arthritis (RA). Furthermore, we investigated the signaling pathways associated with CC receptors as well as the cell type distribution of the receptors.Methods. Using TaqMan real-time reverse transcription-polymerase chain reaction, Western blot analysis, and immunohistochemistry, we defined chemokine and chemokine receptor messenger RNA (mRNA) expression, CC chemokine receptor (CCR) protein activation during the disease course, CCRassociated signaling pathways, and immunopositive CCR5, phosphorylated signal transducer and activator of transcription 1 (p-STAT-1), and p-STAT-3 cells in rat AIA versus control joints.Results. We showed significant up-regulation of CCR1, CCR2, CCR5, and macrophage inflammatory protein 1␤/CCL4 mRNA in AIA on post-adjuvant injection day 18, coincident with peak inflammation. Additionally, increases in tyrosine phosphorylation of CCR1 (days 14, 18, 21, and 24), CCR2 (days 14 and 18), and CCR5 (days 14, 18, and 21) were detected in AIA rats compared with control (nonarthritic) rats. JAK-1, STAT-1, and STAT-3 were associated with CCR1 and were highly tyrosine phosphorylated on days 14 and 18. Rheumatoid arthritis (RA) is an inflammatory disorder characterized by infiltration of monocytes, T cells, and polymorphonuclear cells into the synovial joints. The CC chemokines monocyte chemoattractant protein 1 (MCP-1)/CCL2, macrophage inflammatory protein 1␣ (MIP-1␣)/CCL3, MIP-1␤/CCL4, and

Chemokines and their receptors in rheumatoid arthritis: Future targets?

“…My laboratory has examined chemokine receptor expression and function in rat AIA (120). Using realtime polymerase chain reaction, we showed significant up-regulation of CCR1, CCR2, CCR5, and MIP-1␤/ CCL4 mRNA on postadjuvant injection day 18, coincident with peak joint inflammation.…”

Inhibition of Monocyte Chemoattractant Protein-1 Ameliorates Rat Adjuvant-Induced Arthritis

“…The mean percentage of reactivity was determined for three high power fields in the STs of five separate animals in each treatment group for each cell type and Ab analyzed. Each slide was evaluated by a single blinded pathologist (G. Haines) (13,20). Inflammation (1, normal; 2, increased number of inflammatory cells, arrayed as individual cells; 3, increased number of inflammatory cells, including distinct clusters (aggregates); 4, marked diffuse infiltrate of inflammatory cells) was scored on a 1-4 scale, as described (20).…”

“…Nitrocellulose membranes were blocked with 5% nonfat milk in TBST buffer-20 mM Tris, 137 mM NaCl (pH 7.6), with 0.1% Tween 20 for 60 min at room temperature. Blots were incubated with anti-p-p38 MAPK and anti-p38 MAPK Abs (Cell Signaling Technology) at 1:1000, in TBST containing 5% nonfat milk overnight (13). Blots were scanned and band intensities were determined using UN-SCAN-IT version 5.1 software (Silk Scientific).…”

“…In an animal model of rheumatoid arthritis, adjuvant-induced arthritis (AIA), CCR1, CCR2, and CCR5 mRNA expression and receptor tyrosine phosphorylation are coincident with peak inflammation within the ST (13). During the course of AIA, RANTES levels rise and peak in peripheral blood between days 8 and 12 postadjuvant injection, declining thereafter (14).…”

Prothymosin α Lacking the Nuclear Localization Signal as an Effective Gene Therapeutic Strategy in Collagen-Induced Arthritis

“…Therefore, MIP-1␣ plays an important role in the pathogenesis of RA by recruiting monocytes. In rodent models of CIA and adjuvant-induced arthritis, elevated expression of MIP-1␣ was observed in the ankle joint (38,39). Passive immunization with anti-MIP-1␣ Ab inhibited the development of arthritis in anti-type II collagen Ab-induced arthritis and delayed the onset and reduced the severity of CIA (38,40).…”