THI0019 is an agonist of very late antigen-4 (VLA-4) integrin that induces progenitor cell adhesion. THI0019 greatly enhanced the adhesion of cultured cell lines and primary progenitor cells to α4β1 ligands VCAM-1 and CS1 under both static and flow conditions. Furthermore, THI0019 facilitated the rolling and spreading of cells on VCAM-1 and the migration of cells toward SDF-1α. Molecular modeling predicted that the compound binds at the α/β subunit interface overlapping the ligand-binding site thus indicating that the compound must be displaced upon ligand binding. Co-administering progenitor cells with a compound such as THI0019 may provide a mechanism for enhancing stem cell therapy.
