In Silico Identification and Experimental Validation of Novel Anti-Alzheimer's Multitargeted Ligands from a Marine Source Featuring a "2-Aminoimidazole plus Aromatic Group" Scaffold.

Multitargeting or polypharmacological approaches, looking for single chemical entities retaining the ability to bind two or more molecular targets, are a potentially powerful strategy to fight complex, multifactorial pathologies. Unfortunately, the search for multiligand agents is challenging because only a small subset of molecules contained in molecular databases are bioactive and even fewer are active on a preselected set of multiple targets. However, collections of natural compounds feature a significantly higher fraction of bioactive molecules than synthetic ones. In this view, we searched our library of 1175 natural compounds from marine sources for molecules including a 2-aminoimidazole+aromatic group motif, found in known compounds active on single relevant targets for Alzheimer's disease (AD). This identified two molecules, a pseudozoanthoxanthin (1) and a bromo-pyrrole alkaloid (2), which were predicted by a computational approach to possess interesting multitarget profiles on AD target proteins. Biochemical assays experimentally confirmed their biological activities. The two compounds inhibit acetylcholinesterase, butyrylcholinesterase, and ß-secretase enzymes in high- to sub-micromolar range. They are also able to prevent and revert ß-amyloid (Aß) aggregation of both Aß1-40 and Aß1-42 peptides, with 1 being more active than 2. Preliminary in vivo studies suggest that compound 1 is able to restore cholinergic cortico-hippocampal functional connectivity.

Design, Synthesis, and Evaluation of Donepezil-Like Compounds as AChE and BACE-1 Inhibitors.

An ecofriendly synthetic pathway for the synthesis of donepezil precursors is described. Alternative energy sources were used for the total synthesis in order to improve yields, regioselectively, and rate of each synthetic step and to reduce the coproduction of waste at the same time. For all products, characterized by an improved structural rigidity respect to donepezil, the inhibitor activity on AChE, the selectivity vs BuChE, the side-activity on BACE-1, and the effect on SHSY-5Y neuroblastoma cells viability were tested. Two potential new lead compounds for a dual therapeutic strategy against Alzheimer's disease were envisaged.

Nondenaturing polyacrylamide gel electrophoresis to study the dissociation of the p53·MDM2/X complex by potentially anticancer compounds.

A new analytical method to study the dissociation of the complexes between the oncosuppressor p53 and its negative modulators murine double-minute protein 2 (MDM2) or MDMX, is proposed. This technique is reliable to determine the dissociative power exerted by small molecules on the complex taking advantage of the appearance of migrating MDM2 or MDMX in a native polyacrylamide gel, when inhibitors are added to the complex mixture. Therefore, we propose this new approach to easily screen library of compounds, with potential pharmacological anticancer activity.

Native PAGE to study the interaction between the oncosuppressor p53 and its protein ligands.

In the present study, we investigated a new approach for studying the interaction between p53 and MDM2/X (where MDM is murine double minute protein). The method is based on the different mobility between the interacting domains of the oncosuppressor p53 and its protein ligands MDM2/X on polyacrylamide gels under native conditions. While the two proteins MDM2/X alone were able to enter the gel, the formation of a binary complex between p53 and MDM2/X prevented the gel entry. The novel technique is reliable for determining the different affinity elicited by MDM2 or MDMX toward p53, and can be useful for analyzing the dissociation power exerted by other molecules on the p53-MDM2/X complex.

The cold-adapted γ-glutamyl-cysteine ligase from the psychrophile Pseudoalteromonas haloplanktis.

A recombinant γ-glutamyl-cysteine ligase from the psychrophile Pseudoalteromonas haloplanktis (rPhGshA II) was produced and characterised. This enzyme catalyses the first step of glutathione biosynthesis by forming γ-glutamyl-cysteine from glutamate and cysteine in an ATP-dependent reaction. The other ATP-dependent enzyme, glutathione synthetase (rPhGshB), involved in the second step of the biosynthesis, was already characterised. rPhGshA II is a monomer of 58 kDa and its activity was characterised through a direct radioisotopic method, measuring the rate of ATP hydrolysis. The enzyme was active even at cold temperatures in a moderately alkaline buffer containing a high concentration of Mg(++); 2-aminobutyrate could replace cysteine, although a lower activity was detected. The reaction rate of rPhGshA II at 15 °C was higher than that reported for rPhGshB, thus suggesting that formation of γ-glutamyl-cysteine was not the rate limiting step of glutathione biosynthesis in P. haloplanktis. rPhGshA II had different affinities for its substrates, as evaluated on the basis of the KM values for ATP (0.093 mM), glutamate (2.8 mM) and cysteine (0.050 mM). Reduced glutathione acted as an inhibitor of rPhGshA II, probably through the binding to an enzyme pocket different from the active site. Also the oxidised form of glutathione inhibited the enzyme with a more complex inhibition profile, due to the complete mono-glutathionylation of rPhGshA II on Cys 386, as proved by mass spectrometry data. When compared to rPhGshB, rPhGshA II possessed more typical features of a psychrophilic enzyme, as it was endowed with lower thermodependence and higher heat sensitivity. In conclusion, this work extends the knowledge on glutathione biosynthesis in the first cold-adapted source; however, another possible redundant γ-glutamyl-cysteine ligase (PhGshA I), not yet characterised, could participate in the biosynthesis of this cellular thiol in P. haloplanktis.

UbcH10 expression on thyroid fine-needle aspirates.

BACKGROUND: Thyroid fine-needle aspiration (FNA) samples belonging to the follicular neoplasm/suspicious for malignancy classes are controversial. The authors identified UbcH10 as a marker useful in the diagnosis of several neoplasms, including thyroid cancer. Here, analysis of UbcH10 expression by quantitative reverse transcriptase polymerase chain reaction (RT-PCR) and immunohistochemistry was applied to FNAs. METHODS: A series of 84 follicular neoplasm/suspicious for malignancy FNAs with histological follow-up (30 malignant) was prospectively collected. UbcH10 immunostaining was performed on cell blocks and compared with that of the proliferation marker Ki-67. At the mRNA level, UbcH10 was compared with CCND2 and PCSK2 expression, these latter being the best performing components of the previously reported 3-gene assay; to determine the diagnostic accuracy, the area under the curve (AUC) of the receiver operating characteristic (ROC) curve for each gene individually and in combination was evaluated. RESULTS: UbcH10 and Ki-67 shared a similar pattern; although UbcH10 expression was higher in malignant than in benign lesions (P < .001), staining was sporadic, and the cutoff value derived by the ROC analysis was too low (1.25%) for routine application. Conversely, UbcH10 expression assessment by quantitative RT-PCR was effective. UbcH10 mRNA levels associated with malignant histology were significantly higher than those associated with benign histology (P = .02). The AUC was 0.74 for UbcH10, 0.81 for CCDN2, 0.62 for PCSK2, and 0.84 for UbcH10 and CCND2 combination. CONCLUSIONS: UbcH10 quantitative RT-PCR analysis, rather than immunohistochemistry, is useful to increase the detection of malignancy in thyroid FNAs. UbcH10 may be added as a panel component in quantitative RT-PCR-based assays.