Killing arthritogenic fibroblast-like synoviocytes: an example using cytotoxic aptamers binding nucleolin.

"Pauci-immune" and "fibroblast-rich" synovial pathotypes are predictors of resistance to multi-drug immunosuppression. For these "difficult-to-treat" (D2T) endotypes of rheumatoid arthritis (RA), depletion of arthritogenic fibroblast-like synoviocytes (FLS) has emerged as promising treatment strategy. Profiling at a single-cell level has enabled the molecular characterization of distinct subpopulations of arthritogenic FLS. Advances in molecular engineering have empowered the development of multiple modalities (anti-FLS antibodies, T-cell engagers, cytotoxic cells with chimeric receptors recognizing FLS-specific antigens) to achieve depletion of arthritogenic subpopulations of FLS with unprecedented selectivity. A recently published study highlighted in this article, adds apoptosis-promoting aptamers in the armamentarium of the FLS-killing pipeline.