Multivalent structure of galectin-1-nanogold complex serves as potential therapeutics for rheumatoid arthritis by enhancing receptor clustering

Cellular behaviour is controlled by numerous processes, including intracellular signalling pathways that are triggered by the binding of ligands with cell surface receptors. Multivalent ligands have multiple copies of a recognition element that binds to receptors and influences downstream signals. Nanoparticle-ligand complexes may form multivalent structures to crosslink receptors with high avidity and specificity. After conjugation of galectin-1 onto gold nanoparticles, the resulting nanogold-galectin-1 (Au-Gal1) bound with higher affinity to Jurkat cells to promote CD45 clustering and inhibition of its phosphatase activity, resulting in enhancement of apoptosis via caspase-dependent pathways. Au-Gal1 injected intra-articularly into rats with collagen-induced arthritis (CIA) promoted apoptosis of CD4⁺ T cells and reduced pro-inflammatory cytokine levels in the ankle joints as well as ameliorated clinical symptoms of arthritis. These observed therapeutic effects indicate that the multivalent structure of nanoparticle-ligands can regulate the distribution of cell surface receptors and subsequent intracellular signalling, and this may provide new insights into nanoparticle applications.