The proposed research explores molecular approaches for the study and regulation of aberrant metalloenzyme activity in human disease, focusing on the structural and chemical biology of histone deacetylase (HDAC) isozymes 6, 8, and 10. Dysfunctional HDAC8 mutants are identified in Cornelia de Lange Syndrome (CdLS), a congenital birth defect that occurs in one out of 10,000 births. HDAC8 mutants are potential therapeutic targets for molecular activators that can restore catalytic function. HDAC6, the tubulin deacetylase, is a validated target for cancer chemotherapy and is the only HDAC isozyme containing two independent catalytic domains. Curiously, these domains exhibit remarkably different substrate specificity. Finally, HDAC10 is a cytosolic isozyme like HDAC6, but HDAC10 is not an HDAC in vitro; surprisingly, it is a polyamine deacetylase. If HDAC10 serves this function in vivo, this unexpected chemistry may underlie its role in mediating autophagy. To advance our understanding of structure and function in this important family of metalloenzymes, and to enable innovative molecular approaches for new disease therapies, we aim to pursue the following lines of investigation: (1) We will fully characterize the reaction kinetics and determine X-ray crystal structures of new HDAC8 mutants identified in CdLS. We will determine crystal structures of complexes with peptide/protein substrates and transition state analogues to determine how CdLS mutations perturb enzyme-substrate recognition and catalysis. Additionally, we will study complexes with a small molecule activator to determine the structural basis for the rescue of catalysis in CdLS HDAC8 mutants. (2) We will determine whether HDAC6 CD1 and CD2 domains utilize a single or dual general base-general acid mechanism for catalysis. We will additionally explore the exceptionally narrow substrate specificity of the CD1 domain in order to illuminate its biological function as a deacetylase. Finally, we will determine the structural basis of HDAC6-selective inhibition by determining crystal structures of enzyme-inhibitor complexes to ascertain the importance of a novel Zn2+ coordination mode exploited by HDAC6-selective inhibitors. (3) Finally, we will determine whether HDAC10 utilizes a single or dual general base-general acid mechanism for polyamine deacetylation, and we will confirm its cellular function as the cytosolic N8- acetylspermidine deacetylase. Additionally, we will determine crystal structures of HDAC10 complexes with inhibitors to provide a foundation for the development of HDAC10-selective inhibitors. Such inhibitors will allow us and others to probe the biological function of HDAC10 in studies of cellular polyamine metabolism and autophagy.
This research program explores molecular approaches for the study and regulation of aberrant metalloenzyme activity in human disease, focusing on the structural and chemical biology of histone deacetylase (HDAC) isozymes 6, 8, and 10. Understanding HDAC8 dysfunction in Cornelia de Lange Syndrome will inform clinicians, genetic counselors, and patient families regarding the clinical severity of HDAC8 mutants associated with this congenital birth defect and may also suggest a possible route for therapeutic management. HDAC6 and HDAC10 are drug targets for cancer chemotherapy and neurological disorders; detailed structure-function studies of these isozymes will illuminate new avenues for the design of inhibitors with improved potency and selectivity.
| Bhatia, Sanil; Krieger, Viktoria; Groll, Michael et al. (2018) Discovery of the First-in-Class Dual Histone Deacetylase-Proteasome Inhibitor. J Med Chem 61:10299-10309 |
| Porter, Nicholas J; Osko, Jeremy D; Diedrich, Daniela et al. (2018) Histone Deacetylase 6-Selective Inhibitors and the Influence of Capping Groups on Hydroxamate-Zinc Denticity. J Med Chem 61:8054-8060 |
| Mackwitz, Marcel K W; Hamacher, Alexandra; Osko, Jeremy D et al. (2018) Multicomponent Synthesis and Binding Mode of Imidazo[1,2- a]pyridine-Capped Selective HDAC6 Inhibitors. Org Lett 20:3255-3258 |
| Shinsky, Stephen A; Christianson, David W (2018) Polyamine Deacetylase Structure and Catalysis: Prokaryotic Acetylpolyamine Amidohydrolase and Eukaryotic HDAC10. Biochemistry 57:3105-3114 |
| Porter, Nicholas J; Wagner, Florence F; Christianson, David W (2018) Entropy as a Driver of Selectivity for Inhibitor Binding to Histone Deacetylase 6. Biochemistry 57:3916-3924 |
| Porter, Nicholas J; Mahendran, Adaickapillai; Breslow, Ronald et al. (2017) Unusual zinc-binding mode of HDAC6-selective hydroxamate inhibitors. Proc Natl Acad Sci U S A 114:13459-13464 |
| Hai, Yang; Shinsky, Stephen A; Porter, Nicholas J et al. (2017) Histone deacetylase 10 structure and molecular function as a polyamine deacetylase. Nat Commun 8:15368 |
| Bitler, Benjamin G; Wu, Shuai; Park, Pyoung Hwa et al. (2017) ARID1A-mutated ovarian cancers depend on HDAC6 activity. Nat Cell Biol 19:962-973 |
| Porter, Nicholas J; Christianson, David W (2017) Binding of the Microbial Cyclic Tetrapeptide Trapoxin A to the Class I Histone Deacetylase HDAC8. ACS Chem Biol 12:2281-2286 |
| Gantt, Sister M Lucy; Decroos, Christophe; Lee, Matthew S et al. (2016) General Base-General Acid Catalysis in Human Histone Deacetylase 8. Biochemistry 55:820-32 |
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