The chemokine fragment CXCL9(74–103) diminishes neutrophil recruitment and joint inflammation in antigen-induced arthritis

Abstract

This study investigates if treatment with a peptide corresponding to the 30 C-terminal amino acids of CXCL9, CXCL9(74-103), ameliorates joint inflammation in a murine model of antigen-induced arthritis (AIA). AIA was induced in male C57BL/6J mice. Intravenous injection of CXCL9(74-103), simultaneously performed with a tibiofemoral challenge with methylated BSA (mBSA) as antigen in mice immunized with mBSA, diminished the accumulation of leukocytes, in particular neutrophils, in the synovial cavity. The levels of the chemokines CXCL1, CXCL2, and CXCL6 and of the cytokine IL-6 were decreased in inflamed periarticular tissue of mice treated with the CXCL9-derived peptide compared to non-treated AIA mice. In addition, CXCL9(74-103) treatment substantially reduced joint and cartilage damage. CXCL9(74-103) competes with CXCL6 and CCL3 for binding to the glycosaminoglycans heparan sulfate and chondroitin sulfate in vitro. In vivo, CXCL9(74-103) quickly binds to blood vessels in joints as observed by confocal microscopy. Next, we evaluated if later treatment with CXCL9(74-103) had a beneficial impact on joint inflammation. CXCL9(74-103) injection 6 h after mBSA challenge still reduced neutrophil accumulation in the joint, although it did not reduce chemokine and IL-6 concentrations. However, a delay of treatment until 12 h after challenge had no effect on cell recruitment and chemokine and IL-6 levels. Taken together, we demonstrated that treatment with a peptide, which interferes with the interaction between chemokines and glycosaminoglycans, from the beginning of the disease controlled the massive accumulation of neutrophils in the joint of AIA mice, greatly impacting on joint inflammation and tissue damage.

Targeting Chemokine—Glycosaminoglycan Interactions to Inhibit Inflammation

“…CXCL9 bound with high affinity to soluble and cellular GAGs. The longest 30 amino acid peptide, CXCL9 , was the most potent competitor and competed with CXCL8, muCXCL1, muCXCL6, CXCL11, CCL2, and CCL3 for binding to GAGs (174,231,264). This indicated that CXCL9(74-103) may compete with a wide variety of chemokines that belong to different subclasses.…”

Promising Therapeutic Targets for Treatment of Rheumatoid Arthritis

“…CXCR3, CXCR4, and CXCR5 enhance Th1 cells, lymphocytes, B cells, and T follicular helper (Tfh) cells into joint, respectively (100,103). However, CXCL9 can diminish neutrophil recruitment of joints (104). As shown in Table 1, inhibitors or antagonists of these targets have shown good results in animals, such as CXCR3, CXCR4, CXCL10, CXCL12, and CXCL13, especially the antibody of CXCL10 (MDX-1100) has entered clinical trials (25) (Figure 2).…”

Development of Molecules Antagonizing Heparan Sulfate Proteoglycans

“…7,124,125 The group further evaluated the potency of this CXCL9 peptide in antigen-induced arthritis, where it depicted comparable potency in neutrophil influx attenuation and reduced joint and cartilage damage was observed. 126 Another peptide used in cancer therapy is SSTN 92-119 , also called synstatin. For the activation of αvβ3 integrin, which is upregulated in tumor cells, a capture between IGF1R and αvβ3 integrin by syndecan-1 is necessary, which leads to tumor survival.…”