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bioRxiv · 10.1101/2022.11.12.516260

High-Contrast PET imaging with -NT160, a Class-IIa Histone Deacetylase (Class-IIa HDAC) Probe for In Vivo Imaging of Epigenetic Machinery in the Central Nervous System

Turkman, N.·Xu, S.·Huang, C.-H.·Eyermann, C.·Salino, J.·Khan, P.
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Abstract

We utilized positron emission tomography (PET) imaging in vivo to map the spatiotemporal biodistribution/expression (protein density) of class-IIa histone deacetylases (class-IIa HDACs) in the brain. Herein, we report an improved radiosynthesis of [18F]-NT160 using 4-hydroxy-TEMPO which led to a significant improvement in radiochemical yield and molar activity. PET imaging with [18F]-NT160, a highly potent class-IIa HDAC inhibitor with sub-nM affinity for HDAC4 and 5 isoforms, led to high-quality and high-contrast images among various brain regions. [18F]-NT160 displayed excellent pharmacokinetic and imaging characteristics: brain uptake is high in gray matter regions, leading to high-quality PET images; tissue kinetics are appropriate for an 18F tracer and specific binding for class-IIa HDACs is demonstrated by self-blockade. Higher uptake with [18F]-NT160 was observed in the hippocampus, thalamus, and cortex while there was relatively lower uptake in the cerebellum and striatum. Overall, our current studies with [18F]-NT160 will likely facilitate the development and clinical translation of class-IIa HDACs of the next generation of PET tracers for imaging and targeted therapy of cancer and the diseases of the central nervous system (CNS).

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Turkman, N., Xu, S., Huang, C.-H., Eyermann, C., Salino, J., Khan, P.. 2022-11-13. High-Contrast PET imaging with -NT160, a Class-IIa Histone Deacetylase (Class-IIa HDAC) Probe for In Vivo Imaging of Epigenetic Machinery in the Central Nervous System. https://doi.org/10.1101/2022.11.12.516260

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