Evaluation of miR-211-5p overexpression effect on ER stress-induced apoptosis in Fibroblast-like synoviocytes (FLSs) of Rheumatoid Arthritis

چکیده مقاله

Background: Fibroblast-like synoviocytes (FLSs) play a major role in the pathogenesis of rheumatoid arthritis (RA). Studies have shown that endoplasmic reticulum (ER) stress is involved in resistance to apoptosis of RA-FLSs. miR-211 plays an important role in controlling ER stress-induced apoptosis in a PERK-ATF4-dependent manner. This study aimed to investigate the effect of miR-211-5p overexpression on the induction of ER stress-related apoptosis in RA-FLSs.

Methods: The cell identification was performed after the isolation of FLSs from the synovial tissues of RA and trauma patients. MTT assay was performed to evaluate the cytotoxic effects of thapsigargin (Tg) on RA-FLSs. miR-211-5p and mRNA expression of the genes involved in the PERK pathway and apoptosis regulation were measured in RA, trauma, and Tg-treated RA-FLSs. Afterward, Tg-treated RA-FLSs following miR-211-5p overexpression were evaluated for miR-211-5p and mRNA expression levels of the studied genes.

Results: The expression levels of miR-211-5p, PERK, Bax, and Bcl-2 showed no differences between RA and trauma FLSs. However, the expression of ATF4 and Bcl-XL showed a significant increase in trauma FLSs compared to RA-FLSs. In addition, the levels of CHOP and Mcl-1 indicated a significant increase in RA-FLSs compared to trauma FLSs. Tg treatment significantly increased the expression of the PERK-related genes in RA-FLSs with no effect on miR-211-5p and the genes involved in apoptosis regulation. Furthermore, Tg treatment following miR-211-5p overexpression in RA-FLSs showed a significant increase in levels of miR-211-5p but did not alter the expression of CHOP and apoptosis regulation genes.

Conclusion: Based on the results, it seems that there is ER stress in RA and trauma FLSs. Stimulation of ER stress in RA-FLSs, despite increasing the ER stress markers, did not alter the expression of miR-211-5p and selected genes related to apoptosis regulation. In addition, overexpression of miR-211-5p in stimulated RA-FLSs did not change the expression of CHOP and the selected apoptosis-regulating genes. Further studies are needed to determine the ER stress role in apoptosis regulation in RA-FLSs.

Keywords: Fibroblast-like synoviocytes (FLSs), Rheumatoid arthritis, ER stress, miR-211-5p, Apoptosis