Mirror-image ligand discovery enabled by single-shot fast-flow synthesis of D-proteins.

Widespread adoption of mirror-image biological systems presents difficulties in accessing the requisite D-protein substrates. In particular, mirror-image phage display has the potential for high-throughput generation of biologically stable macrocyclic D-peptide binders with potentially unique recognition modes but is hindered by the individualized optimization required for D-protein chemical synthesis. We demonstrate a general mirror-image phage display pipeline that utilizes automated flow peptide synthesis to prepare D-proteins in a single run. With this approach, we prepare and characterize 12 D-proteins - almost one third of all reported D-proteins to date. With access to mirror-image protein targets, we describe the successful discovery of six macrocyclic D-peptide binders: three to the oncoprotein MDM2, and three to the E3 ubiquitin ligase CHIP. Reliable production of mirror-image proteins can unlock the full potential of D-peptide drug discovery and streamline the study of mirror-image biology more broadly.

Detecting the Knowledge Domains of Compound Semiconductors.

The development of compound semiconductors (CS) has received extensive attention worldwide. This study aimed to detect and visualize CS knowledge domains for quantifying CS research patterns and emerging trends through a scientometric review based on the literature between 2011 and 2020 by using CiteSpace. The combined dataset of 24,622 bibliographic records were collected through topic searches and citation expansion to ensure adequate coverage of the field. While research in "solar cell" and "perovskite tandem" appears to be the two most distinctive knowledge domains in the CS field, research related to thermoelectric materials has grown at a respectable pace. Most notably, the deep connections between "thermoelectric material" and "III-Sb nanowire (NW)" research have been demonstrated. A rapid adaptation of black phosphorus (BP) field-effect transistors (FETs) and gallium nitride (GaN) transistors in the CS field is also apparent. Innovative strategies have focused on the opto-electronics with engineered functionalities, the design, synthesis and fabrication of perovskite tandem solar cells, the growing techniques of Sb-based III-V NWs, and the thermal conductivity of boron arsenide (BAs). This study revealed how the development trends and research areas in the CS field advance over time, which greatly help us to realize its knowledge domains.

Binary combinatorial scanning reveals potent poly-alanine-substituted inhibitors of protein-protein interactions.

Establishing structure-activity relationships is crucial to understand and optimize the activity of peptide-based inhibitors of protein-protein interactions. Single alanine substitutions provide limited information on the residues that tolerate simultaneous modifications with retention of biological activity. To guide optimization of peptide binders, we use combinatorial peptide libraries of over 4,000 variants-in which each position is varied with either the wild-type residue or alanine-with a label-free affinity selection platform to study protein-ligand interactions. Applying this platform to a peptide binder to the oncogenic protein MDM2, several multi-alanine-substituted analogs with picomolar binding affinity were discovered. We reveal a non-additive substitution pattern in the selected sequences. The alanine substitution tolerances for peptide ligands of the 12ca5 antibody and 14-3-3 regulatory protein are also characterized, demonstrating the general applicability of this new platform. We envision that binary combinatorial alanine scanning will be a powerful tool for investigating structure-activity relationships.

Chelation-Tamoxifen Conjugates for Imaging of Estrogen Receptors.

Background: The differential diagnosis of estrogen receptor-positive (ER+) pathway-activated systems by using a labeled antiestrogen helps to select the patients for optimal response to endocrine therapy and to discontinue the treatment when resistance occurs. The authors' purpose was to synthesize chelator-tamoxifen conjugates for imaging ER (+) diseases. Materials and Methods: A hydroxypropyl linker was incorporated between either cyclam or cyclam diacetic acid and tamoxifen analog to produce SC-05-L-1 (Z-1-(1,4,8,11-tetraazacyclotetradecan-1-yl)-3-((5-(4-(2-(diethylamino)ethoxy)phenyl)-4,5-diphenylpent-4-en-1-yl)oxy)propan-2-ol) and SC-05-N-1 (Z-2,2'-(4-(3-((5-(4-(2-(diethylamino)ethoxy)phenyl)-4,5-diphenylpent-4-en-1-yl)oxy)-2-hydroxy-propyl)-1,4,8,11-tetraazacyclotetradecane-1,8-diyl)diacetic acid), respectively. In vitro cell uptake and cell/media ratios of 99mTc-SC-05-L-1 and 99mTc- SC-05-N-1 in ER (+) ovarian cancer cells (TOV-112D and OVCAR3) were performed. To ascertain the specificity of cell uptake, the cell uptake was blocked with estrone. In vivo 99mTc-SC-05-L-1 or 99mTc-SC-05-N-1 single-photon emission computed tomography/computed tomography was conducted in tumor-bearing rodents and compared to 18F-fluoro-2-deoxy-d-glucose (18F-FDG) positron emission tomography/magnetic resonance imaging (a reference technology). Results: The radiochemical purities of 99mTc-SC-05-L-1 and 99mTc-SC-05-N-1 were greater than 99% (n = 10). 99mTc-SC-05-L-1 had higher cell/media ratios than 99mTc-SC-05-N-1 in OVCAR-3 ER (+) cells. The cell uptake of 99mTc-SC-05-L-1 was blocked 80% by estrone indicating an ER-mediated process occurred. 99mTc-SC-05-N-1 was further selected for in vivo imaging studies due to higher maximum tolerated dose and superior water solubility than 99mTc-SC-05-L-1. 99mTc-SC-05-N-1 showed higher tumor uptake and tumor/muscle count density ratios than 18F-FDG in tumor-bearing rodents. Conclusion: 99mTc-SC-05-N-1 showed better differential diagnosis of ovarian tumors than 18F-FDG, indicating great promising in chelator-tamoxifen conjugate for ER pathway-directed systems imaging.

A Hybrid Fuzzy Decision Model for Evaluating MEMS and IC Integration Technologies.

Integrated devices incorporating MEMS (microelectromechanical systems) with IC (integrated circuit) components have been becoming increasingly important in the era of IoT (Internet of Things). In this study, a hybrid fuzzy MCDM (multi-criteria decision making) model was proposed to effectively evaluate alternative technologies that incorporate MEMS with IC components. This model, composed of the fuzzy AHP (analytic hierarchy process) and fuzzy VIKOR (VIseKriterijumska Optimizacija I Kompromisno Resenje) methods, solves the decision problem of how best to rank MEMS and IC integration technologies in a fuzzy environment. The six important criteria and the major five alternative technologies associated with our research themes were explored through literature review and expert investigations. The priority weights of criteria were derived using fuzzy AHP. After that, fuzzy VIKOR was deployed to rank alternatives. The empirical results show that development schedule and manufacturing capability are the two most important criteria and 3D (three-dimensional) SiP (system-in-package) and monolithic SoC (system-on-chip) are the top two favored technologies. The proposed fuzzy decision model could serve as a reference for the future strategic evaluation and selection of MEMS and IC integration technologies.

De Novo Discovery of High-Affinity Peptide Binders for the SARS-CoV-2 Spike Protein.

The ß-coronavirus SARS-CoV-2 has caused a global pandemic. Affinity reagents targeting the SARS-CoV-2 spike protein are of interest for the development of therapeutics and diagnostics. We used affinity selection-mass spectrometry for the rapid discovery of synthetic high-affinity peptide binders for the receptor binding domain (RBD) of the SARS-CoV-2 spike protein. From library screening with 800 million synthetic peptides, we identified three sequences with nanomolar affinities (dissociation constants K d = 80-970 nM) for RBD and selectivity over human serum proteins. Nanomolar RBD concentrations in a biological matrix could be detected using the biotinylated lead peptide in ELISA format. These peptides do not compete for ACE2 binding, and their site of interaction on the SARS-CoV-2-spike-RBD might be unrelated to the ACE2 binding site, making them potential orthogonal reagents for sandwich immunoassays. These findings serve as a starting point for the development of SARS-CoV-2 diagnostics or conjugates for virus-directed delivery of therapeutics.

Does muscle improve validated outcome measures in open tibial fractures? New insights from a cohort study of the anterolateral thigh flap (ALT) versus ALT-Vastus lateralis flaps.

The benefits of the muscle in open lower limb fractures remain to be determined. This study compared statistically equivalent groups of open tibial fractures treated by free anterolateral thigh (ALT) flaps or ALT flaps incorporating muscle (ALT-Vastus lateralis/ALT- VL). Method and Results: Chang Gung Memorial Hospital, Taiwan, 2004-2008, 49 free flaps in open lower limb fractures (38 open tibial) were specifically reconstructed with free ALT or ALT-VL flaps. Risk factors for non-union: equivalent between the two groups, with no differences in smoking, steroids, diabetes, time to flap and the AO classification of soft tissue and bone injury. Comparison of union rates: no difference was noted between groups in the Radiographic Union Score in Tibial Fractures (RUST) at 3, 6, 9 and 12 months. The only factor significantly associated with non-union was presence of a SPRINT trial defined 'critical' bone defect with odds ratio 14.4 (95% CI 1.36 - 131.5), with no association with AO bone classification, flap type, comorbidity or flap size. Patient-reported outcomes: the ALT-VL group showed improved patient satisfaction (p = 0.01, Cohen's d = 1.1). Functional outcomes (Enneking score) were not statistically significant, but the ALT-VL group trended towards significance in function and skin quality domains. Conclusions: Based on the results of this study, one can conclude that the degree of bone injury (specifically a 'critical' defect) is of greater relevance than flap choice with regard to fracture consolidation. Muscle does not result in improvements to union, the speed of union or deep infection. However, better PROMs may be related to the inclusion of the muscle around the fracture site.

A Platinum(IV) Prodrug-Perfluoroaryl Macrocyclic Peptide Conjugate Enhances Platinum Uptake in the Brain.

Effective delivery to the brain limits the development of novel glioblastoma therapies. Here, we introduce conjugation between platinum(IV) prodrugs of cisplatin and perfluoroaryl peptide macrocycles to increase brain uptake. We demonstrate that one such conjugate shows efficacy against glioma stem-like cells. We investigate the pharmacokinetics of this conjugate in mice and show that the amount of platinum in the brain after treatment with the conjugate is 15-fold greater than with cisplatin after 5 h.

A novel, potent, and orally bioavailable thiazole HCV NS5A inhibitor for the treatment of hepatitis C virus.

A medicinal chemistry program based on the small-molecule HCV NS5A inhibitor daclatasvir has led to the discovery of dimeric phenylthiazole compound 8, a novel and potent HCV NS5A inhibitor. The subsequent SAR studies and optimization revealed that the cycloalkyl amide derivatives 27a-29a exhibited superior potency against GT1b with GT1b EC50 values at picomolar concentration. Interestingly, high diastereospecificity for HCV inhibition was observed in this class with the (1R,2S,1'R,2'S) diastereomer displaying the highest GT1b inhibitory activity. The best inhibitor 27a was found to be 3-fold more potent (GT1b EC50 = 0.003 nM) than daclatasvir (GT1b EC50 = 0.009 nM) against GT1b, and no detectable in vitro cytotoxicity was observed (CC50 > 50 µM). Pharmacokinetic studies demonstrated that compound 27a had an excellent pharmacokinetic profiles with a superior oral exposure and desired bioavailability after oral administration in both rats and dogs, and therefore it was selected as a developmental candidate for the treatment of HCV infection.

Ligand-Directed Divergent Synthesis of Carbo- and Heterocyclic Ring Systems.

Chemical tools that enable a catalytic reaction to selectively and efficiently yield different products will allow charting of wider chemical space. In ligand-directed divergent synthesis, a common mode of catalysis is modulated by employing different ligands for catalytic organometallic complexes to transform either common substrates or common reactive intermediates into distinct molecular scaffolds. The strategy has the potential to create important and diverse scaffolds and to unveil novel modes of catalytic transformations for wider synthetic applications. This strategy is described and recent efforts in this emerging field of catalysis, focusing on transition-metal catalysis for the synthesis of carbo- and heterocyclic ring systems, are reviewed.

A ligand-directed divergent catalytic approach to establish structural and functional scaffold diversity.

The selective transformation of different starting materials by different metal catalysts under individually optimized reaction conditions to structurally different intermediates and products is a powerful approach to generate diverse molecular scaffolds. In a more unified albeit synthetically challenging strategy, common starting materials would be exposed to a common metal catalysis, leading to a common intermediate and giving rise to different scaffolds by tuning the reactivity of the metal catalyst through different ligands. Herein we present a ligand-directed synthesis approach for the gold(I)-catalysed cycloisomerization of oxindole-derived 1,6-enynes that affords distinct molecular scaffolds following different catalytic reaction pathways. Varying electronic properties and the steric demand of the gold(I) ligands steers the fate of a common intermediary gold carbene to selectively form spirooxindoles, quinolones or df-oxindoles. Investigation of a synthesized compound collection in cell-based assays delivers structurally novel, selective modulators of the Hedgehog and Wnt signalling pathways, autophagy and of cellular proliferation.

A Potent, Selective, and Orally Bioavailable HCV NS5A Inhibitor for Treatment of Hepatitis C Virus: (S)-1-((R)-2-(Cyclopropanecarboxamido)-2-phenylacetyl)-N-(4-phenylthiazol-2-yl)pyrrolidine-2-carboxamide.

Starting from the initial lead 4-phenylthiazole 18, a modest HCV inhibitor (EC50 = 9440 nM), a series of structurally related thiazole derivatives has been identified as a novel chemical class of potent and selective HCV NS5A inhibitors. The introduction of a carboxamide group between the thiazole and pyrrolidine ring (42) of compound 18 resulted in a dramatic increase in activity (EC50 = 0.92 nM). However, 42 showed only moderate pharmacokinetic properties and limited oral bioavalability of 18.7% in rats. Further optimization of the substituents at the 4-position of the thiazole ring and pyrrolidine nitrogen of the lead compound 42 led to the identification of compound 57, a highly potent and selective NS5A inhibitor of HCV (EC50 = 4.6 nM), with greater therapeutic index (CC50/EC50 > 10000). Pharmacokinetic studies revealed that compound 57 had a superior oral exposure and desired bioavailability of 45% after oral administration in rats.

Moderate to severe, but not mild, nonalcoholic fatty liver disease associated with increased risk of gallstone disease.

OBJECTIVE: Nonalcoholic fatty liver disease (NAFLD) and gallstone disease (GSD) share some of the same risk factors. The association between NAFLD and GSD was inconsistent. Moreover, there are no studies on the association between GSD and the severity of NAFLD in the literature. The aim of this study was to determine the relationship between the severity of NAFLD and GSD in a Taiwanese population. MATERIALS AND METHODS: A total of 12,033 subjects were enrolled. The diagnoses of GSD and NAFLD were based on the finding of abdominal ultrasonography. The severity of NAFLD was divided into mild, moderate, and severe. RESULTS: Compared with the non-GSD group, the GSD one was older and had a higher BMI, blood pressure, fasting plasma glucose, cholesterol, triglyceride, and higher prevalence of diabetes and hypertension, but they had a lower eGFR and HDL-C level and less prevalence of current smoking and alcohol drinking. There was a significant difference in the severity of NAFLD between subjects with and without GSD. Based on logistic regression, age ≥65 versus <40 years, 40-64.9 versus <40 years, female, current alcohol drinking, diabetes, hypertension, HDL-C level and moderate to severe NAFLD, but not mild NAFLD, were the independently associated risk factors of GSD. CONCLUSION: Moderate to severe, but not mild, NAFLD was associated with an increased risk of GSD, independent of the traditional cardio-metabolic risk factor. Age, female, diabetes, and hypertension were also related to a higher risk of GSD, but HDL-C level and moderate alcohol drinking showed a lower risk.

3D-QSAR-assisted drug design: identification of a potent quinazoline-based Aurora kinase inhibitor.

We describe the 3D-QSAR-assisted design of an Aurora kinase A inhibitor with improved physicochemical properties, in vitro activity, and in vivo pharmacokinetic profiles over those of the initial lead. Three different 3D-QSAR models were built and validated by using a set of 66 pyrazole (Model I) and furanopyrimidine (Model II) compounds with IC(50) values toward Aurora kinase A ranging from 33 nM to 10.5 µM. The best 3D-QSAR model, Model III, constructed with 24 training set compounds from both series, showed robustness (r(2) (CV) =0.54 and 0.52 for CoMFA and CoMSIA, respectively) and superior predictive capacity for 42 test set compounds (R(2) (pred) =0.52 and 0.67, CoMFA and CoMSIA). Superimposition of CoMFA and CoMSIA Model III over the crystal structure of Aurora kinase A suggests the potential to improve the activity of the ligands by decreasing the steric clash with Val147 and Leu139 and by increasing hydrophobic contact with Leu139 and Gly216 residues in the solvent-exposed region of the enzyme. Based on these suggestions, the rational redesign of furanopyrimidine 24 (clog P=7.41; Aurora A IC(50) =43 nM; HCT-116 IC(50) =400 nM) led to the identification of quinazoline 67 (clog P=5.28; Aurora A IC(50) =25 nM; HCT-116 IC(50) =23 nM). Rat in vivo pharmacokinetic studies showed that 67 has better systemic exposure after i.v. administration than 24, and holds potential for further development.

Anti-influenza drug discovery: identification of an orally bioavailable quinoline derivative through activity- and property-guided lead optimization.

From a high-throughput screening (HTS) hit with inhibitory activity against virus-induced cytophathic in the low micromolar range, we have developed a potent anti-influenza lead through careful optimization without compromising the drug-like properties of the compound. An orally bioavailable compound was identified as a lead agent with nanomolar activity against influenza, representing a 140-fold improvement over the initial hit.

Isatin-ß-thiosemicarbazones as potent herpes simplex virus inhibitors.

A series of isatin-ß-thiosemicarbazones have been designed and evaluated for antiviral activity against herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) in a plaque reduction assay. Their cytotoxicity was examined using human rhabdomyosarcoma cells (RD cells). Several derivatives of isatin-ß-thiosemicarbazone exhibited significant and selective antiviral activity with low cytotoxicity. It was found that the thiourea group at thiosemicarbazone and the NH functionality at isatin were essential for their antiherpetic activity. The synthesis and structure-activity relationship studies are presented.

Synthesis, activity, and pharmacokinetic properties of a series of conformationally-restricted thiourea analogs as novel hepatitis C virus inhibitors.

A series of novel conformationally-restricted thiourea analogs were designed, synthesized, and evaluated for their anti-HCV activity. Herein we report the synthesis, structure-activity relationships (SARs), and pharmacokinetic properties of this new class of thiourea compounds that showed potent inhibitory activities against HCV in the cell-based subgenomic HCV replicon assay. Among compounds tested, the fluorene compound 4b was found to possess the most potent activity (EC(50)=0.3 microM), lower cytotoxicity (CC(50)>50 microM), and significantly better pharmacokinetic properties compared to its corresponding fluorenone compound 4c.

Design and efficient synthesis of novel arylthiourea derivatives as potent hepatitis C virus inhibitors.

A novel class of arylthiourea HCV inhibitors bearing various functionalities, such as cyclic urea, cyclic thiourea, urea, and thiourea, on the alkyl linker were designed and synthesized. Herein we report the synthesis and structure-activity relationships (SARs) of this novel class of arylthiourea derivatives that showed potent inhibitory activities against HCV in the cell-based subgenomic HCV replicon assay. Among compounds tested, the new carbazole derivative 64, which has an eight-carbon linkage between the phenyl and carbazole rings and a tolyl group at the N-9 position of carbazole, was found to possess strong anti-HCV activity (EC50=0.031 microM), lower cytotoxicity (CC50 >50 microM), and higher selectivity index (SI >1612) compared to its derivatives.