title: Development of a novel bioavailable inhibitor of the calmodulin-regulated protein kinase MLCK: a lead compound that attenuates vascular leak.
abstract: Tissue barriers involving epithelial and endothelial cell layers are critical to homeostasis, regulating passage of water, macromolecules, cells and certain classes of small molecules via two distinct cellular mechanisms, transcellular or paracellular. Endothelial or epithelial barrier dysfunction is a key component of pathophysiology in diverse diseases and injuries that have a broad impact on survival and quality of life. However, effective and safe small molecule therapeutics for these disorders are lacking. Success in development would therefore fill a major unmet medical need across multiple disease areas. Myosin light chain kinase (MLCK), a highly specialized calcium/calmodulin (CaM) regulated protein kinase, modulates barrier function through its regulation of intracellular contractile processes. MLCK levels and activity are increased in various animal models of disease and in human clinical disease samples. Our prior work with a genetic knockout (KO) mouse strain for the long form of MLCK, MLCK210, has identified MLCK as a drug discovery target for endothelial and epithelial barrier dysfunction. We describe here the development of a selective, bioavailable, stable inhibitor of MLCK that attenuates barrier dysfunction in mice comparable to that seen with the MLCK KO mice. The inhibitor compound 6 is stable in human microsomal metabolic stability assays and can be synthesized in a high-yielding and facile synthetic process. These results provide a foundation for and demonstrate the feasibility of future medicinal chemistry refinement studies directed toward the development of novel therapies for disorders involving barrier dysfunction.
authors.affiliation: Center for Drug Discovery and Chemical Biology, Northwestern University, 303 E. Chicago Avenue, Mail Code W896, Chicago, IL 60611, USA.
authors.forename: Heather A
authors.initials: HA
authors.lastname: Behanna
authors.forename: D Martin
authors.initials: DM
authors.lastname: Watterson
authors.forename: Hantamalala
authors.initials: H
authors.lastname: Ralay Ranaivo
mesh_terms: D000818:Animals; D001681:Biological Assay; D005260:Female; D006801:Humans; D020128:Inhibitory Concentration 50; D051379:Mice; D008810:Mice, Inbred C57BL; D008862:Microsomes, Liver / Q000187:drug effects; D009219:Myosin-Light-Chain Kinase / Q000037:antagonists & inhibitors*; D047428:Protein Kinase Inhibitors / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D011724:Pyridazines / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D011759:Pyrrolidines / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*
chemical_list: C516557:11-(6-imino-3-phenylpyridazin-1(6H)-yl)-N-(2-(1-methylpyrrolidin-2-yl)ethyl)undecanamide; D047428:Protein Kinase Inhibitors; D011724:Pyridazines; D011759:Pyrrolidines; D009219:Myosin-Light-Chain Kinase