Extensive genetic analysis beyond targeted CYP21A2 mutational detection is often required to accurately determine genotype in patients with CAH due to the high frequency of complex genetic variation.

CAH-X syndrome is commonly found in CAH due to 21-hydroxylase deficiency and may result from various etiological mechanisms.

Recognizing acetyllysine of histone is a vital process of epigenetic regulation that is mediated by a protein module called bromodomain. To contribute novel scaffolds for developing into bromodomain inhibitors, we utilize a fragment-based drug discovery approach. By successively applying docking and X-ray crystallography, we were able to identify 9 fragment hits from diffracting more than 60 crystals. In the present work, we described four of them and carried out the integrated lead optimization for fragment 8, which bears a 2-thiazolidinone core. After several rounds of structure guided modifications, we assessed the druggability of 2-thiazolidinone by modulating in vitro pharmacokinetic studies and cellular activity assay. The results showed that two potent compounds of 2-thiazolidinones have good metabolic stability. Also, the cellular assay confirmed the activities of 2-thiazolidinones. Together, we hope the identified 2-thiazolidinone chemotype and other fragment hits described herein can stimulate researchers to develop more diversified bromodomain inhibitors.

Clinical evaluation for connective tissue dysplasia should be routinely performed in CAH patients, especially those harboring a CYP21A2 deletion.

β-Secretase (β-site amyloid precursor protein-cleaving enzyme 1; BACE1) is a transmembrane aspartic protease that cleaves the β-amyloid precursor protein en route to generation of the amyloid β-peptide (Aβ) that is believed to be responsible for the Alzheimer's disease amyloid cascade. It is thus a prime target for the development of inhibitors which may serve as drugs in the treatment and/or prevention of Alzheimer's disease. In the following determination of the crystal structures of both apo and complexed BACE1, structural analysis of all crystal structures of BACE1 deposited in the PDB and molecular dynamics (MD) simulations of monomeric and `dimeric' BACE1 were used to study conformational changes in the active-site region of the enzyme. It was observed that a flap able to cover the active site is the most flexible region, adopting multiple conformational states in the various crystal structures. Both the presence or absence of an inhibitor within the active site and the crystal packing are shown to influence the flap's conformation. An open conformation of the flap is mostly observed in the apo structures, while direct hydrogen-bonding interaction between main-chain atoms of the flap and the inhibitor is a prerequisite for the flap to adopt a closed conformation in the crystal structures of complexes. Thus, a systematic study of the conformational flexibility of the enzyme may not only contribute to structure-based drug design of BACE1 inhibitors and of other targets with flexible conformations, but may also help to better understand the mechanistic events associated with the binding of substrates and inhibitors to the enzyme.

No abstract

Inspired by marine cyanobacterial natural products, we synthesized modified peptides with a central statine-core unit, characteristic for aspartic protease inhibition. A series of tasiamide B analogues inhibited BACE1, a therapeutic target in Alzheimer's disease. We probed the stereospecificity of target engagement and determined additional structure-activity relationships with respect to BACE1 and related aspartic proteases, cathepsins D and E. We cocrystallized selected inhibitors with BACE1 to reveal the structural basis for the activity. Hybrid molecules that combine features of tasiamide B and an isophthalic acid moiety-containing sulfonamide showed nanomolar cellular activity. Compounds were screened in a series of rigorous complementary cell-based assays. We measured secreted APP ectodomain (sAPPβ), membrane bound carboxyl terminal fragment (CTF), levels of β-amyloid (Aβ) peptides and selectivity for β-secretase (BACE1) over γ-secretase. Prioritized compounds showed reasonable stability in vitro and in vivo, and our most potent inhibitor showed efficacy in reducing Aβ levels in the rodent brain.

Acute myeloid leukemia is a disorder characterized by abnormal differentiation of myeloid cells and a clonal proliferation derived from primitive hematopoietic stem cells. Interventions that overcome myeloid differentiation have been shown to be a promising therapeutic strategy for acute myeloid leukemia. In this study, we demonstrate that CRISPR/Cas9-mediated knockout of dihydroorotate dehydrogenase leads to apoptosis and normal differentiation of acute myeloid leukemia cells, indicating that dihydroorotate dehydrogenase is a potential differentiation regulator and a therapeutic target in acute myeloid leukemia. By screening a library of natural products, we identified a novel dihydroorotate dehydrogenase inhibitor, isobavachalcone, derived from the traditional Chinese medicine Psoralea corylifolia. Using enzymatic analysis, thermal shift assay, pull down, nuclear magnetic resonance, and isothermal titration calorimetry experiments, we demonstrate that isobavachalcone inhibits human dihydroorotate dehydrogenase directly, and triggers apoptosis and differentiation of acute myeloid leukemia cells. Oral administration of isobavachalcone suppresses subcutaneous HL60 xenograft tumor growth without obvious toxicity. Importantly, our results suggest that a combination of isobavachalcone and adriamycin prolonged survival in an intravenous HL60 leukemia model. In summary, this study demonstrates that isobavachalcone triggers apoptosis and differentiation of acute myeloid leukemia cells via pharmacological inhibition of human dihydroorotate dehydrogenase, offering a potential therapeutic strategy for acute myeloid leukemia.