Developing High Content Imaging Functional Panels to Characterize Synovial Fibroblasts in Rheumatoid Arthritis

Abstract

ObjectiveTo develop and apply a preclinical functional imaging assay for visualizing and analyzing activated synovial fibroblasts (SFs) at single-cell resolution using high-content imaging. MethodsA multiparametric functional imaging assay was developed to simultaneously interrogate six key cellular processes in cultured SFs from non-inflammatory control (NIC), osteoarthritis (OA) and rheumatoid arthritis (RA) patients. Two complementary fluorescent panels -- comprising LipidTOX, MitoSOX, TMRM, EdU Click-iT, CYTO-ID, and Sir-Lysosome -- collectively captured autophagy dynamics, mitochondrial health, lipid metabolism, and cellular proliferation within a single imaging workflow. Automated image acquisition and quantitative feature extraction via CellProfiler yielded approximately 1,200 morphological and intensity-based features per cell, enabling high-dimensional, unbiased phenotypic profiling at the individual cell level. ResultsApplication of this assay revealed marked heterogeneity in basal cellular functions among SFs stratified by disease state, and robustly differentiated between NIC, OA and RA SFs. Stimulation with inflammatory cytokines (TNF-, IL-1{beta}, IFN{gamma}) and toll-like receptor ligands (LPS, poly I:C) elicited distinct, stimulus-dependent phenotypic responses across disease groups. Multiparametric analysis and feature importance ranking identified IL-1{beta} as a key driver of enhanced autophagic activity, accompanied by significant remodeling of lipid metabolic profiles. ConclusionWe developed a scalable, sensitive approach for dissecting functional heterogeneity in primary SF cultures, revealing previously unappreciated complexity in SF biology across disease states. Our approach provides a robust framework for high-throughput drug screening and identification of candidate therapeutics selectively targeting pathogenic fibroblast functions in inflammatory arthritis.