Modulation of acute inflammation by targeting glycosaminoglycan-cytokine interactions

Glycosaminoglycans (GAGs) located on cellular membranes and the extracellular matrix (ECM) are able to interact with chemokines and pro-inflammatory cytokines, leading to local cytokine/chemokine accumulation. The tissue-bound cytokines/chemokines function in promoting leukocyte migration and activation, contributing to local inflammation. Hence, targeting of GAG-cytokine interactions may provide an avenue for the attenuation of inflammatory responses. A cationic peptide (MC2) derived from the heparin-binding sequence of mouse IFN-γ was previously shown by our laboratory to delay allograft rejection in an animal model. In order to further investigate potential anti-inflammatory properties of the MC2 peptide, we have studied its activity in an acute peritoneal inflammation model. Groups of C57Bl/6 mice were injected intraperitoneally with either ConA or thioglycollate and treated with saline (control), the MC2 peptide or two control cationic peptides, poly-l-lysine (PLL) and poly-l-arginine (PLA). Treatment with the MC2 peptide, but not PLA or PLL, resulted in statistically significant reductions in total cell numbers, concentration of total proteins and concentrations of pro-inflammatory cytokines (TNFα, IL-6 or IL-1β) in peritoneal lavage fluids, without alterations to the qualitative cellular composition of the exudate. These results suggest that targeting GAG-cytokine interaction is a viable approach to reduce inflammation.