Exploring the NCS-382 Scaffold for CaMKIIα Modulation: Synthesis, Biochemical Pharmacology, and Biophysical Characterization of Ph-HTBA as a Novel High-Affinity Brain-Penetrant Stabilizer of the CaMKIIα Hub Domain
Yongsong Tian, Mohamed A. Shehata, Stine Juul Gauger, Carolina Veronesi, Louise Hamborg, Louise Thiesen, Jesper Bruus‐Jensen, Johanne Schlieper Royssen, Ulrike Leurs, Anne Sofie G. Larsen, Jacob Krall, Sara M. Ø. Solbak, Petrine Wellendorph, Bente Frølund
Abstract
Ca2+/calmodulin-dependent protein kinase II alpha (CaMKIIα) is a brain-relevant kinase and an emerging drug target for ischemic stroke and neurodegenerative disorders. Despite reported CaMKIIα inhibitors, their usefulness is limited by low subtype selectivity and brain permeability. (E)-2-(5-Hydroxy-5,7,8,9-tetrahydro-6H-benzo[7]annulen-6-ylidene)acetic acid (NCS-382) is structurally related to the proposed neuromodulator, γ-hydroxybutyric acid, and is a brain-penetrating high nanomolar-affinity ligand selective for the CaMKIIα hub domain. Herein, we report the first series of NCS-382 analogs displaying improved affinity and preserved brain permeability. Specifically, we present Ph-HTBA (1i) with enhanced mid-nanomolar affinity for the CaMKIIα binding site and a marked hub thermal stabilization effect along with a distinct CaMKIIα Trp403 flip upon binding. Moreover, Ph-HTBA has good cellular permeability and low microsomal clearance and shows brain permeability after systemic administration to mice, signified by a high Kp, uu value (0.85). Altogether, our study highlights Ph-HTBA as a promising candidate for CaMKIIα-associated pharmacological interventions and future clinical development.