Effect of rc-3095, an antagonist of gastrin-releasing peptide receptor, on fibroblast-like synovyocites : a potential new strategy for arthritis treatment

Abstract

Introduction: Gastrin-releasing peptide (GRP) is a functional homologue of bombesin, and its receptor signaling is involved in several functions, including inflammatory response. GRP and its receptor (GRPR) have been found in synovial membrane and fluid of rheumatoid arthritis patients. RC-3095 is an antagonist of GRPR. Objective: evaluate the role of gastrin-releasing peptide, its receptor and RC-3095 on fibroblast-like synovyocites (FLS) in RA development. Methods: Mouse DBA/1J FLS were isolated from the tarsus of the hind paws of collagen-induced arthritis. FLS immunocitochemistry was executed to evaluate the GRPR presence. Then, it was evaluated FLS viability treated with RC-3095 in 24 h and 48 h. After this, FLS proliferation stimulated with LPS or GRP was performed by MTT assay in 24h. Finally, invasion assay was realized in a transwell system using Matrigel-coated inserts and treated with GRP, RC-3095, GRP+RC-3095. Results: Immunocitochemistry confirmed the presence of GRPR in FLS and its antagonist was not cytotoxic for FLS. Any statistical difference was observed in proliferation assay. Although, in invasion assay GRP was able to increase FLS invasion and RC-3095 or GRP+RC-3095 treatment comparing with GRP was able to decrease FLS invasion. Conclusion: This is the first study to identify the presence of GRPR in FLS. GRP causes an increase in the FLS invasion and RC-3095 was able to reverse this effect. Therefore the interference on GRP pathway is a potential target for the treatment of rheumatoid arthritis using RC-3095 for future clinical trials.