Luminometric Nanoparticle-Based Assay for High Sensitivity Detection of ß-Amyloid Aggregation.

A nanoparticle-based assay utilizing time-resolved luminescence resonance energy transfer (TR-LRET) was developed for the detection of ß-amyloid aggregation. The assay is based on the competitive adsorption of the sample and the acceptor-labeled protein to donor europium(III) polystyrene nanoparticles. The performance of the assay was demonstrated by following the fibrillization of ß-amyloid peptide 1-42 (Aß42) as a function of time and by comparing to the reference methods atomic force microscopy (AFM) and thioflavin T (ThT) assay. The fibrillization leads to reduced adsorption of Aß42 to the nanoparticles increasing the TR-LRET signal. The investigated methods detected fibril formation with equal sensitivities. Eight potential fibrillization inhibitor compounds reported in the literature were tested and the results obtained with each method were compared. It was shown with AFM imaging that the inhibition of fibril formation was not complete with any of the compounds. The developed TR-LRET nanoparticle assay gave corresponding results with the AFM imaging. However, the ThT assay led to contradictory results, as low fluorescence signal was measured in the presence of all tested compounds suggesting inhibition of fibrillization. Our results suggest that the developed TR-LRET nanoparticle assay can be exploited for screening of potential ß-amyloid aggregation inhibitors, whereas some of the tested compounds may be measured as false positive inhibitors with the much-utilized ThT assay.

Discovery of small molecules with vasodilating characteristics and adjustable hydrolytic behavior.

In this contribution the development of a new class of vasodilating compounds obtained by lead structure optimization is described. Three groups of compounds were synthesized and tested for their activity on various smooth muscle preparations of the guinea pig. Beside the lead compound 3a, the most interesting derivative was 1H-imidazole-1-carbothioic acid O-cyclohexyl ester hydrochloride (5b) with a good selective vasodilating potential on aorta and pulmonary artery rings (EC50 14 µM and 24 µM, respectively). Due to the properties of small molecules the hydrolysis behavior of the compounds can be easily adapted hence opening a new route in terms of duration of the agent's effect. With the aid of structure-activity relationship studies, structural motifs influencing the biological activity on isolated smooth muscle cell preparations of the synthesized compounds were proposed. The presented compounds offer good tools in identifying promising molecules as emergency therapy in myocardial infarction.

SAR-guided development and characterization of a potent antitumor compound toward B-cell neoplasms with no detectable cytotoxicity toward healthy cells.

Acute hematological diseases (leukemias and aggressive lymphomas) can be cured in approximately half of the patients, while the other patients die from their disease. Chronic leukemias and indolent lymphomas can be well controlled for years in most cases. However, the cure rate of these patients is low and the course of the disease is characterized by frequent recurrence. Therefore, novel agents for monotherapies or combination therapies still need to be explored. The presented study describes the identification of the chalcone derivative 15 on different types of human malignant cells of the lymphoid and myeloid lineage. Further experiments performed with compound 15 on peripheral blood mononuclear cells (PBMCs) of chronic lymphocytic leukemia (CLL) patients clearly stated a higher cytotoxicity in PBMC from CLL patients compared to healthy donors (HD). The newly identified chalcone derivative 15 showed a higher therapeutic potential than fludarabine, a drug already in use in lymphoma treatment.