Engineered 3D Fibronectin‐Based Environments Modulate the Pathogenic Profile of Arthritic Synovial Fibroblasts

Inflammation is essential for fighting infections and initiating tissue repair, but chronic unresolved inflammation underlies many conditions, like cancer and autoimmune disorders. While dysregulated immune responses drive chronic inflammation, non‐immune stromal cells such as fibroblasts also play a critical role. Targeting fibroblasts could enable tissue‐specific therapies while avoiding the systemic suppression caused by current drugs. However, traditional culture systems often induce artificial behaviors, limiting progress. Here, we demonstrate the importance of 3D culture environments to regulate fibroblast‐mediated inflammation in vitro in the context of Rheumatoid Arthritis, a chronic disease that primarily affects joints. We isolated synovial fibroblasts from healthy and arthritic mouse joints and expanded them on 2D tissue culture plastic, fibronectin‐coated porous scaffolds, or pegylated fibronectin‐based hydrogels, to investigate how commonly used in vitro culture platforms influence fibroblast behavior. Our results highlight the plasticity of fibroblasts, with microenvironmental cues driving platform‐dependent fibroblast changes in vitro. The 3D environment offered by porous scaffolds recapitulated the inflammatory and proliferative gene expression profiles that were lost in flat cultures, while hydrogels shifted fibroblasts toward reduced inflammatory pathway activation. These findings underscore the importance of the culture environments in modulating fibroblast behavior and establish a foundation for bioengineered systems that better model disease in vitro .