A Cyclosporin Derivative Discriminates between Extracellular and Intracellular Cyclophilins

Trimesic acid amide serves as a scaffold for a lipophilic cyclophilin inhibitor, a fluorescent rhodamine dye (TAMRA), and a (D-Glu)6 oligopeptide residue. Although the affinity of 1 for intracellular cyclophilin A (CypA) is very high, fluorescence measurements indicate complete exclusion from the cell. CypA-induced chemotaxis of lymphocytes is inhibited by 1 since extracellular cyclophilins are responsible for the physiological signal.