An Engineered Multivalent TMV Nanodisk Platform for Modulating Integrin Clustering and Cell Signaling

Clustering of cell-surface receptors is essential for initiating signaling cascades and regulating cellular functions. Multivalent ligands with high receptor affinity offer powerful tools for manipulating these processes and advancing therapeutic strategies. However, designing easily modifiable, stable, and uniformly structured multivalent ligands remains a significant challenge. In this work, we present a novel protein-based platform derived from modified tobacco mosaic virus (TMV) coat protein, which assembles into a stable, discoid scaffold capable of displaying up to 34 ligands with evenly distributed binding sites. By introducing the T103C modification, we achieve exceptional structural stability, allowing the platform to maintain integrity across a broad pH range (5-11) and during long-term storage (up to 6 months). Using the integrin-binding peptide SPPEPS as a model, we generate a multivalent TMV-SPPEPS that exhibits a 453-fold increase in integrin affinity over the monomeric peptide and can simultaneously cluster up to seven integrins. This multivalent platform promotes integrin clustering on cell surfaces, triggering mesenchymal stem cell chondrogenesis and effectively alleviating osteoarthritis in a rat model. These results highlight the potential of the TMV nanodisk as a versatile and stable platform for controlling receptor clustering and modulating intracellular signaling in diverse biomedical applications.