Selective inhibition of ROCK kinase isoforms to promote neuroregeneration after brain surgery

Abstract

The Rho-associated protein kinase (ROCK) is an essential regulator of Rho signaling pathways in a variety of cellular processes, which has been established as a potential therapeutic target to promote neuroregeneration after brain surgery. The kinase family contains two highly homologous, tissue-specific isoforms ROCK1 and ROCK2, and selective inhibition of them would result in distinct biological effects in neurotherapy. The two kinase isoforms have only a slight difference across their active sites, but structural components out of the sites seem to confer exquisite specificity for selective binding of inhibitor ligands to ROCK1 and ROCK2. Here, a quantitative structure–selectivity relationship model is developed to characterize the relative contribution of each kinase residue to inhibitor selectivity. The model was then used to screen against a panel of known kinase inhibitors, from which five compounds with high theoretical selectivity are tested in vitro using a kinase assay protocol to determine their biological activity and selectivity. Consequently, the compound CAY10576 is found to have moderate and high inhibitory potencies against ROCK1 and ROCK2 (IC50 = 1.8 and 0.04 μM, respectively) as well as strong selectivity between the two isoforms (S = −1.65), which could be considered as a good lead entity to develop potent, selective ROCK inhibitors to promote neurogenesis and neuroregeneration.