Therapeutic targeting of CDC-like kinase 1 by bioactive polyphenols for Alzheimer's disease intervention

Alzheimer's disease (AD) is a chronic, debilitating neurodegenerative condition that represents the primary cause of clinical dementia. The two main pathobiological features of the AD include widespread neuroinflammation and severe degradation of synapses. CDC-like kinase 1 (CLK1) is a dual-specificity protein kinase that has been found to regulate MAPT exon10 splicing and has become an attractive therapeutic target in AD treatment. Nonetheless, the recent repertoire of specific and high-potent CLK1 inhibitors is also limited, which highlights the need to develop more. In our research, we examined the inhibitory properties of two naturally occurring compounds, cinchonine (CN) and resveratrol (RS) on CLK1 using a multidisciplinary approach that combined spectroscopic methodologies, enzyme kinetic studies, molecular docking, molecular dynamics (500 ns), and cell-based studies. Fluorescence quenching, time-resolved spectroscopy and circular dichroism experiments confirmed that there was a strong binding affinity along with ligand induced structural modulation. CN and RS both showed concentration-dependent viability in SHSY5Y neuroblastoma cells. Molecular docking with 500 ns all-atom molecular dynamics simulations has shown that these ligands have strong, stable affinity in the ATP binding pocket of CLK1. Accordingly, the present paper characterizes the physicochemical and mechanistic interaction of CN and RS with CLK1 that was systematically studied by in-vitro and i n-silico approaches.Taken together, the results lay the foundation for further therapeutic application of these natural compounds and their derivatives for AD and other CLK1-related diseases after necessary in vivo validation.