Synthesis and Biological Evaluation of Novel Membrane-Permeant Cyclic ADP-Ribose Mimics:N~1-[(5'-O-Phosphorylethoxy)methyl]-5'-O-phosphorylinosine 5',5'-Cyclicpyrophosphate(cIDPRE)and 8-Substituted Derivatives

摘要

N~1-[(5"-O-Phosphorylethoxy)methyl]-5'-O-phosphorylinosine 5',5"-cyclicpyrophosphate(cIDPRE 2a)and the 8-substituted derivatives 8-bromo-,8-azido-,8-amino-,and 8-Cl-cIDPRE(2b-e)were synthesized from N~1-[(5"-acetoxyethoxy)methyl]-2',3/-O-isopropylideneinosine(5)in good yields.The pharmacological activities of cIDPRE and the 8-substituted derivatives(2a-e)were analyzed in intact and permeabilized human Jurkat T-lymphocytes.The results indicate that cIDPRE permeates the plasma membrane,releases Ca~(2+)from an intracellular,cADPR-sensitive Ca~(2+)store,and subsequently initiates Ca~(2+)release-activated Ca~(2+)entry.The Ca~(2+)-releasing activity of cIDPRE was confirmed directly in permeabilized cells.Using time-resolved confocal Ca~(2+)imaging at the single cell level,the development of global Ca~(2+)signals starting from local small Ca~(2+)signals evoked by cIDPRE was observed.8-N_3-cIDPRE 2c and 8-NH_2-cIDPRE 2d were similarly effective in their agonistic activity as compared to cIDPRE 2a,showing almost indistinguishable concentration-response curves for 2a,2c,and 2d and very similar kinetics of Ca~(2+)signaling.In contrast,the halogenated derivatives 8-Br-and 8-Cl-cIDPRE(2b and 2e)did not significantly elevate [Ca~(2+)]i.Therefore,cIDPRE 2a,8-N_3-cIDPRE 2c,and 8-NH_2-cIDPRE 2d are novel membrane permeant cADPR mimic and may provide important novel tools to study cADPR-mediated Ca~(2+)signaling in intact cells.