E64FC26 inhibits inflammation and joint destruction in rheumatoid arthritis models

Background and objectives

Protein disulfide isomerases (PDIs) are essential enzymes that facilitate the proper folding of proteins and maintain protein quality within the endoplasmic reticulum. Dysregulation of PDIs has been correlated with numerous disorders, including cancer and rheumatoid arthritis (RA). E64FC26 (EFC), a small molecule that inhibits a wide range of PDI family members, has shown promise as a therapeutic agent in oncology. However, its effects on RA have not yet been studied. This research investigates the efficacy of EFC as a potential treatment for RA.

Methods

To investigate EFC's effects on RA fibroblast-like synoviocytes, several assays were employed, including Cell Counting Kit-8 for cell viability, EdU for cell proliferation, Transwell for migration and invasion, TUNEL for apoptosis, and in vitro tube formation assays for angiogenesis. Flow cytometry was used to assess apoptosis in detail. Cytokine production was analyzed using ELISA and real-time polymerase chain reaction. In vivo, a collagen-induced arthritis model was developed in DBA mice to evaluate EFC's effects on inflammation, disease progression, and bone damage. RNA sequencing was utilized to identify the molecular pathways influenced by EFC treatment.

Results

EFC exhibited significant anti-inflammatory effects on RA fibroblast-like synoviocytes, reducing cell proliferation, migration, invasion, angiogenic activity, and cytokine secretion, while simultaneously promoting apoptosis. In vivo experiments using the collagen-induced arthritis mouse model showed that EFC alleviated inflammation, slowed disease progression, and preserved joint and bone integrity. RNA sequencing data suggested that EFC acts through pathways associated with inflammation and apoptosis regulation.

Conclusions

Our study shows that EFC reduces the inflammatory phenotype of RA FLSs, significantly lowering inflammation and joint destruction in animal arthritis models. These findings expand on the known functions of EFC, revealing its therapeutic potential for RA alongside its established anti-tumor properties. This highlights the need for lateral thinking, which may facilitate optimal utilization of existing treatments. Furthermore, our research confirms the role of PDIs in promoting RA, providing a foundation for the future application of PDIs as therapeutic targets in RA management.