Design and synthesis of N-benzoyl amino acid derivatives as DNA methylation inhibitors.

The inhibition of human DNA Methyl Transferases (DNMT) is a novel promising approach to address the epigenetic dysregulation of gene expression in different diseases. Inspired by the validated virtual screening hit NSC137546, a series of N-benzoyl amino acid analogues was synthesized and obtained compounds were assessed for their ability to inhibit DNMT-dependent DNA methylation in vitro. The biological screening allowed the definition of a set of preliminary structure-activity relationships and the identification of compounds promising for further development. Among the synthesized compounds, L-glutamic acid derivatives 22, 23, and 24 showed the highest ability to prevent DNA methylation in a total cell lysate. Compound 22 inhibited DNMT1 and DNMT3A activity in a concentration-dependent manner in the micromolar range. In addition, compound 22 proved to be stable in human serum and it was thus selected as a starting point for further biological studies.

An improved sonochemical reactor.

The design and optimization of sonochemical apparatus are still open to advancement. Under high-intensity ultrasound reaction rates and yields are mainly influenced by the characteristics of transducer and reactor. Several useful improvements are introduced and described. In order to achieve uniformity of the acoustic field and optimal acoustic streaming in every part of the reaction vessel (a Teflon tube), the reactor can be made to rotate eccentrically around the horn axis and the probe to move alternatively up and down by a pre-determined excursion at a chosen speed. Continuous high-power irradiation is feasible without any time limit because the whole probe system is refrigerated by an oil forced-circulation circuit connected to a chiller. The apparatus can control a number of important reaction parameters: modified atmosphere, reaction temperature, tunable frequency and constant amplitude. Excellent performance was observed on several reactions, such as the chemical modification of chitosan, a poorly soluble biopolymer.

Electrophilic warhead-based design of compounds preventing NLRP3 inflammasome-dependent pyroptosis.

Pyroptosis is a caspase-1-dependent pro-inflammatory form of programmed cell death implicated in the pathogenesis of autoinflammatory diseases as well as in disorders characterized by excessive cell death and inflammation. Activation of NLRP3 inflammasome is a key event in the pyroptotic cascade. In this study, we describe the synthesis and chemical tuning of α,ß-unsaturated electrophilic warheads toward the development of antipyroptotic compounds. Their pharmacological evaluation and structure-activity relationships are also described. Compound 9 was selected as a model of this series, and it proved to be a reactive Michael acceptor, irreversibly trapping thiol nucleophiles, which prevented both ATP- and nigericin-triggered pyroptosis of human THP-1 cells in a time- and concentration-dependent manner. Moreover, 9 and other structurally related compounds, inhibited caspase-1 and NLRP3 ATPase activities. Our findings can contribute to the development of covalent, multitarget antipyroptotic compounds targeting molecular components of the NLRP3 inflammasome regulatory pathway.