Background:

IC50: 21 nM, 100 nM, and 11.48 μM for HDAC1, 2, and 3, respectively

BRD6688 is an HDAC inhibitor.

A few chromatin modifying enzymes have been implicated in the neurobiology of learning and memory, especially, histone deacetylases (HDACs). HDACs are responsible for catalyzing the posttranslational hydrolysis of acetyl groups from the 3-nitrogen of lysine residues of histone and non-histone proteins.

In vitro: BRD6688 was found to demonstrate kinetic selectivity for HDAC2 against HDAC1, an isoform with 95% similarity within the catalytic binding domain. Moreover, BRD6688 could increase histone acetylation (H4K12 and H3K9) in primary mouse neuronal cultures [1].

In vivo: Mouse in-vivo study showed that BRD6688 was able to increase the histone acetylation (H4K12 and H3K9) in hippocampal CA1 neurons of CK-p25 mice. Moreove, the increased histone acetylation in brain served as a surrogate pharmacodynamic marker of HDAC engagement and was consistent with previously observed brain pharmacokinetic properties. In addition, BRD6688 rescued the cognitive deficits in CK-p25 mice, a model of neurodegeneration, in a Pavlovian fear conditioning behavioral assay [1].

Clinical trial: So far, no clinical study has been conducted.

Reference:
[1] Wagner, F. F.,Zhang, Y.-L.,Fass, D.M., et al. Kinetically selective inhibitors of histone deacetylase 2 (HDAC2) as cognition enhancers. Chem.Sci. 6(1), 804-815 (2015).