Structure-Based Discovery of High-Affinity Small Molecule Ligands and Development of Tool Probes to Study the Role of Chitinase-3-Like Protein 1.

Chitinase-3-like-1 (CHI3L1), also known as YKL-40, is a glycoprotein linked to inflammation, fibrosis, and cancer. This study explored CHI3L1's interactions with various oligosaccharides using microscale thermophoresis (MST) and AlphaScreen (AS). These investigations guided the development of high-throughput screening assays to assess interference of small molecules in binding between CHI3L1 and biotinylated small molecules or heparan sulfate-based probes. Small molecule binders of YKL-40 were identified in our chitotriosidase inhibitors library with MST and confirmed through X-ray crystallography. Based on cocrystal structures of potent hit compounds with CHI3L1, small molecule probes 19 and 20 were designed for an AS assay. Structure-based optimization led to compounds 30 and 31 with nanomolar activities and drug-like properties. Additionally, an orthogonal AS assay using biotinylated heparan sulfate as a probe was developed. The compounds' affinity showed a significant correlation in both assays. These screening tools and compounds offer novel avenues for investigating the role of CHI3L1.

Chemistry of glycol nucleic acid (GNA): Synthesis, photophysical characterization and insight into the biological activity of phenanthrenyl GNA constituents.

The knowledge pertaining to the chemistry and biological activity of glycol nucleic acid (GNA) components, like nucleosides and nucleotides, is still very limited. Herein we report on the preparation of the uracil nucleoside (1) and nucleotide ester GNA (2). The compounds are functionalised with a luminescent phenanthrenyl group. In DMSO, 1 and 2 are brightly fluorescent, with emission maxima at 390 nm, nanosecond decay times (0.6 and 0.75 ns, respectively), and quantum yields of ca. 0.2. In the solid phase, they show excimeric emission, with maxima at 495 nm (1) and 432 nm (2), and decay times of 3.7 ns (1) and 2.9 ns (2). The anticancer activity of the GNA components, as well as gemcitabine hydrochloride, used as a reference drug, were examined in vitro against human cancer HeLa and Ishikawa cells, as well as against normal L929 cells, using a battery of biochemical assays. Furthermore, biodistribution imaging studies were carried out in HeLa cells, with luminescence confocal microscopy, which showed that the compounds localized mainly in the lipophilic cellular compartments. Nucleoside (1) and nucleotide ester (2) features two different anticancer activity profiles. At 24 h of treatment, the nucleoside acts mainly as a toxin and induces necrosis in HeLa cells, whereas the nucleotide ester exhibits pro-apoptotic activity. At longer treatment times (72 h), the nucleoside and the reference, gemcitabine hydrochloride, featured almost identical signs of anticancer activity, such as S-phase cell cycle arrest, proliferation inhibition, and apoptosis induction. In view of this data, one can hypothesize that despite the structural differences, the newly obtained phenanthrenyl GNA nucleoside (1) and gemcitabine may share a common mechanism of anticancer activity in HeLa cancer cells. The GNA components were also examined as antiplasmodial agents against Plasmodium falciparum, in vitro. Nucleoside (1) was found to be more potent than nucleotide (2), displaying activity in the low micromolar range. Furthermore, both phenanthrene derivatives were found to display resistance indices at least 9-fold lower than chloroquine diphosphate (CQDP).

Discovery of OATD-01, a First-in-Class Chitinase Inhibitor as Potential New Therapeutics for Idiopathic Pulmonary Fibrosis.

Chitotriosidase (CHIT1) and acidic mammalian chitinase (AMCase) are the enzymatically active chitinases that have been implicated in the pathology of chronic lung diseases such as asthma and interstitial lung diseases (ILDs), including idiopathic pulmonary fibrosis (IPF) and sarcoidosis. The clinical and preclinical data suggest that pharmacological inhibition of CHIT1 might represent a novel therapeutic approach in IPF. Structural modification of an advanced lead molecule 3 led to the identification of compound 9 (OATD-01), a highly active CHIT1 inhibitor with both an excellent PK profile in multiple species and selectivity against a panel of other off-targets. OATD-01 given orally once daily in a range of doses between 30 and 100 mg/kg showed significant antifibrotic efficacy in an animal model of bleomycin-induced pulmonary fibrosis. OATD-01 is the first-in-class CHIT1 inhibitor, currently completed phase 1b of clinical trials, to be a potential treatment for IPF.

Benzoxazepine-Derived Selective, Orally Bioavailable Inhibitor of Human Acidic Mammalian Chitinase.

Human acidic mammalian chitinase (hAMCase) is one of two true chitinases in humans, the function of which remains elusive. In addition to the defense against highly antigenic chitin and chitin-containing pathogens in the gastric and intestinal contents, AMCase has been implicated in asthma, allergic inflammation, and ocular pathologies. Potent and selective small-molecule inhibitors of this enzyme have not been identified to date. Here we describe structural modifications of compound OAT-177, a previously developed inhibitor of mouse AMCase, leading to OAT-1441, which displays high activity and selectivity toward hAMCase. Significantly reduced off-target activity toward the human ether-à-go-go-related gene (hERG) and a good pharmacokinetic profile make OAT-1441 a potential candidate for further preclinical development as well as a useful tool compound to study the physiological role of hAMCase.

Development of Dual Chitinase Inhibitors as Potential New Treatment for Respiratory System Diseases.

Acidic mammalian chitinase (AMCase) and chitotriosidase-1 (CHIT1) are two enzymatically active proteins produced by mammals capable of cleaving the glycosidic bond in chitin. Based on the clinical findings and animal model studies, involvement of chitinases has been suggested in several respiratory system diseases including asthma, COPD, and idiopathic pulmonary fibrosis. Exploration of structure-activity relationships within the series of 1-(3-amino-1H-1,2,4-triazol-5-yl)-piperidin-4-amines, which was earlier identified as a scaffold of potent AMCase inhibitors, led us to discover highly active dual (i.e., AMCase and CHIT1) inhibitors with very good pharmacokinetic properties. Among them, compound 30 was shown to reduce the total number of cells in bronchoalveolar lavage fluid of mice challenged with house dust mite extract after oral administration (50 mg/kg, qd). In addition, affinity toward the hERG potassium channel of compound 30 was significantly reduced when compared to the earlier reported chitinase inhibitors.

Discovery of selective, orally bioavailable inhibitor of mouse chitotriosidase.

This article describes our work towards the identification of a potent and selective inhibitor of mouse chitotriosidase (mCHIT1). A series of small molecule inhibitors of mCHIT1 and mAMCase have been developed from early lead compound 1. Examination of synthetized analogues led to discovery of several novel highly potent compounds. Among them compound 9 (OAT-2068) displays a remarkable 143-fold mCHIT1 vs. mAMCase selectivity. To explain the observed SAR molecular docking experiments were performed, which were in line with the experimental data from the enzymatic assays. Inhibitor 9 (OAT-2068) was found to have an excellent pharmacokinetic profile. This, together with high activity and selectivity, makes the compound an ideal and unique tool for studying the role of CHIT1 in biological models.

Aerobic palladium(II)-catalyzed dehydrogenative heck reaction in the synthesis of pyrenyl fluorophores. a photophysical study of ß-pyrenyl acrylates in solution and in the solid state.

An aerobic dehydrogenative Heck reaction of pyrene (1a) and 2,7-di-tert-butylpyrene (1b) with ethyl acrylate is reported. The reaction is catalyzed by a Pd(OAc)2/4,5-diazafluoren-9-one (DAF) system and takes place in acetic or pivalic acid as solvents at 110-130 °C. The reaction of 1a afforded a 6:1 mixture of C-1- and C-4-alkenylated pyrenes (2a and 3a, respectively) in 71% yield. In the case of 1b, only a C-4-substituted product (3b) was formed in 46% yield. Compounds 2a and 3a,b exhibited fluorescence in solution and in the solid state. In chloroform and THF solution the fluorescence maxima were in the range of 440-465 nm, and quantum yields decreased in the order 2a > 3a> 3b. In the solid state, 3a,b showed blue-green fluorescence (ΦF = 0.26 and 0.14, respectively), whereas 2a emitted yellow-green fluorescence) (ΦF = 0.35). Besides blue-emitting monomers, the presence of green-emitting aggregated species (preformed dimers) in the crystals of 3a,b and red-emitting dynamic excimers in the crystals of 2a has been demonstrated. Single-crystal X-ray diffraction analyses of 2a and 3b confirmed π-stacking of pyrenyl moieties in the crystals of the former and the absence of stacking in the crystals of the latter compound.

Electron collisions with trifluorides: BF3 and PF3 molecules.

Absolute total cross sections (TCSs) for electron scattering from boron trifluoride (BF(3)) and phosphorus trifluoride (PF(3)) molecules have been measured using a linear transmission method. The electron energy ranges from 0.6 to 370 eV for BF(3) and from 0.5 to 370 eV for PF(3). The TCS energy dependence for BF(3) exhibits two very pronounced enhancements: resonantlike narrow feature located near 3.6 eV with the maximum value of 19.2 x 10(-20) m(2), and intermediate energy very broad enhancement with two humps, one centered around 21 eV (18.8 x 10(-20) m(2) in the maximum) and the other near 45 eV (19.5 x 10(-20) m(2)). For PF(3) the TCS has quite different low-energy dependence: at 0.5 eV it has a high value of 70 x 10(-20) m(2) and decreases steeply towards higher energies. Beyond the minimum near 5.5 eV, the TCS reveals two distinct humps: the resonant one centered near 11 eV with the peak value of 32.9 x 10(-20) m(2) and the second one much broader around 35 eV (27.9 x 10(-20) m(2)). The present TCSs for trifluorides are compared to each other as well as to previous TCS data for selected perfluorides and to results for their perhydrided counterparts. The differences and similarities in the shape and magnitude of TCSs are pointed out.