Kabala PA, et al. - The purpose of this study is to scrutinize if endoplasmic reticulum (ER) stress could regulate inflammatory gene expression in rheumatoid arthritis (RA) fibroblast-like synoviocytes (FLS). The outcome of this study revealed that the RA FLS are resistant to apoptosis induced by ER stress, but ER stress potentiates their activation by multiple Toll-like receptor (TLR) ligands. Interfering with downstream signaling pathway components of ER stress may be of therapeutic potential in the treatment of RA.