From Companion Diagnostics to Theranostics:A New Avenue for Alzheimer's Disease?

The recent literature signals a growing paradigm shift toward integrating therapeutics and diagnostics rather than developing and deploying them separately. In this gradual move toward more effective and personalized medications, companion diagnostics are an intermediate stage. The next step may be "theranostics", in which single chemical entities are developed to deliver therapy and diagnosis simultaneously. This strategy has been successfully exploited in oncology and is now emerging as a possibility for Alzheimer's disease, where its feasibility has caught the attention of researchers from industry and academia. Medicinal chemists do not yet completely understand the nuances of theranostic action and consequently have not yet developed universally validated strategies for developing theranostic clinical applications against Alzheimer's disease. However, given the emerging indications of the potentially enormous benefits that theranostics may bring to the fight against this devastating disease, further rigorous research is warranted

Enriching Proteolysis Targeting Chimeras with a Second Modality: When Two Are Better Than One

Proteolysis targeting chimera (PROTAC)-mediated protein degradation has prompted a radical rethink and is at a crucial stage in driving a drug discovery transition. To fully harness the potential of this technology, a growing paradigm toward enriching PROTACs with other therapeutic modalities has been proposed. Could researchers successfully combine two modalities to yield multifunctional PROTACs with an expanded profile? In this Perspective, we try to answer this question. We discuss how this possibility encompasses different approaches, leading to multitarget PROTACs, light-controllable PROTACs, PROTAC conjugates, and macrocycle-and oligonucleotide-based PROTACs. This possibility promises to further enhance PROTAC efficacy and selectivity, minimize side effects, and hit undruggable targets. While PROTACs have reached the clinical investigation stage, additional steps must be taken toward the translational development of multifunctional PROTACs. A deeper and detailed understanding of the most critical challenges is required to fully exploit these opportunities and decisively enrich the PROTAC toolbox

Location of the Polyamine Binding Site in the Vestibule of the Nicotinic Acetylcholine Receptor Ion Channel

To map the structure of a ligand-gated ion channel, we used the photolabile polyamine-containing toxin MR44 as photoaffinity label. MR44 binds with high affinity to the nicotinic acetylcholine receptor in its closed channel conformation. The binding stoichiometry was two molecules of MR44 per receptor monomer. Upon UV irradiation of the receptor-ligand complex, (125)I-MR44 was incorporated into the receptor alpha-subunit. From proteolytic mapping studies, we conclude that the site of (125)I-MR44 cross-linking is contained in the sequence alpha His-186 to alpha Leu-199, which is part of the extracellular domain of the receptor. This sequence partially overlaps in its C-terminal region with one of the three loops that form the agonist-binding site. The agonist carbachol and the competitive antagonist alpha-bungarotoxin had only minor influence on the photocross-linking of (125)I-MR44. The site where the hydrophobic head group of (125)I-MR44 binds must therefore be located outside the zone that is sterically influenced by agonist bound at the nicotinic acetylcholine receptor. In binding and photocross-linking experiments, the luminal noncompetitive inhibitors ethidium and triphenylmethylphosphonium were found to compete with (125)I-MR44. We conclude that the polyamine moiety of (125)I-MR44 interacts with the high affinity noncompetitive inhibitor site deep in the channel of the nicotinic acetylcholine receptor, while the aromatic ring of this compound binds in the upper part of the ion channel (i.e. in the vestibule) to a hydrophobic region on the alpha-subunit that is located in close proximity to the agonist binding site. The region of the alpha-subunit labeled by (125)I-MR44 should therefore be accessible from the luminal side of the vestibule

Innovative Non-PrP-Targeted Drug Strategy Designed to Enhance Prion Clearance

Prion diseases are a group of neurodegenerative disorders characterized by the accumulation of misfolded prion protein (called PrPSc). Although conversion of the cellular prion protein (PrPC) to PrPSc is still not completely understood, most of the therapies developed until now are based on blocking this process. Here, we propose a new drug strategy aimed at clearing prions without any direct interaction with neither PrPC nor PrPSc. Starting from the recent discovery of SERPINA3/SerpinA3n upregulation during prion diseases, we have identified a small molecule, named compound 5 (ARN1468), inhibiting the function of these serpins and effectively reducing prion load in chronically infected cells. Although the low bioavailability of this compound does not allow in vivo studies in prion-infected mice, our strategy emerges as a novel and effective approach to the treatment of prion disease

Epidemiology and complications of late-onset sepsis: an Italian area-based study

BACKGROUND: Most studies regarding late-onset sepsis (LOS) address selected populations (i.e., neonates with low birth weight or extremely preterm neonates). Studying all age groups is more suitable to assess the burden of single pathogens and their clinical relevance. METHODS: This is a retrospective regional study involving paediatric departments and NICUs in Emilia-Romagna (Italy). Regional laboratory databases were searched from 2009 to 2012. Records of infants (aged 4 to 90 days) with a positive blood or cerebrospinal fluid (CSF) culture were retrospectively reviewed and analysed according to acquisition mode (whether hospital- or community-acquired). RESULTS: During the study period, there were 146,682 live births (LBs), with 296 patients experiencing 331 episodes of LOS (incidence rate: 2.3/1000 LBs). Brain lesions upon discharge from the hospital were found in 12.3% (40/296) of cases, with death occurring in 7.1% (23/296; 0.14/1000 LBs). With respect to full-term neonates, extremely preterm or extremely low birth weight neonates had very high risk of LOS and related mortality (> 100- and > 800-fold higher respectively). Hospital-acquired LOS (n = 209) was significantly associated with very low birth weight, extremely preterm birth, pneumonia, mechanical ventilation, and death (p< 0.01). At multivariate logistic regression analysis, catecholamine support (OR = 3.2), central venous line before LOS (OR = 14.9), and meningitis (OR = 44.7) were associated with brain lesions or death in hospital-acquired LOS (area under the ROC curve 0.81, H-L p = 0.41). Commonly identified pathogens included coagulase-negative staphylococci (CoNS n = 71, 21.4%), Escherichia coli (n = 50, 15.1%), Staphylococcus aureus (n = 41, 12.4%) and Enterobacteriaceae (n = 41, 12.4%). Group B streptococcus was the predominant cause of meningitis (16 of 38 cases, 42%). Most pathogens were sensitive to first line antibiotics. CONCLUSIONS: This study provides the first Italian data regarding late-onset sepsis (LOS) in all gestational age groups. Compared to full-term neonates, very high rates of LOS and mortality occurred in neonates with a lower birth weight and gestational age. Group B streptococcus was the leading cause of meningitis. Excluding CoNS, the predominant pathogens were Escherichia coli and Staphylococcus aureus. Neonates with hospital-acquired LOS had a worse outcome. Antibiotic associations, recommended for empirical treatment of hospital- or community-acquired LOS, were adequate

N-1,2,3-triazole-isatin derivatives for cholinesterase and β-amyloid aggregation inhibition: A comprehensive bioassay study

Our goal was the evaluation of a series of N-1,2,3-triazole-isatin derivatives for multi-target activity which included cholinesterase (ChE) inhibition and β-amyloid (Aβ) peptide anti-aggregation. The compounds have shown considerable promise as butyrylcholinesterase (BuChE) inhibitors. Although the inhibition of eel acet- ylcholinesterase (eeAChE) was weak, the inhibitions against equine BuChE (eqBuChE) and human BuChE (hBuChE) were more significant with a best inhibition against eqBuChE of 0.46 μM. In some cases, these mo- lecules gave better inhibitions for hBuChE than eqBuChE. For greater insights into their mode of action, mole- cular docking studies were carried out, followed by STD-NMR validation. In addition, some of these compounds showed weak Aβ anti-aggregation activity. Hepatotoxicity studies showed that they were non-hepatoxic and neurotoxicity studies using neurite out- growth experiments led to the conclusion that these compounds are only weakly neurotoxic

Naphthoquinone Derivatives Exert Their Antitrypanosomal Activity via a Multi-Target Mechanism

BACKGROUND AND METHODOLOGY: Recently, we reported on a new class of naphthoquinone derivatives showing a promising anti-trypanosomatid profile in cell-based experiments. The lead of this series (B6, 2-phenoxy-1,4-naphthoquinone) showed an ED(50) of 80 nM against Trypanosoma brucei rhodesiense, and a selectivity index of 74 with respect to mammalian cells. A multitarget profile for this compound is easily conceivable, because quinones, as natural products, serve plants as potent defense chemicals with an intrinsic multifunctional mechanism of action. To disclose such a multitarget profile of B6, we exploited a chemical proteomics approach. PRINCIPAL FINDINGS: A functionalized congener of B6 was immobilized on a solid matrix and used to isolate target proteins from Trypanosoma brucei lysates. Mass analysis delivered two enzymes, i.e. glycosomal glycerol kinase and glycosomal glyceraldehyde-3-phosphate dehydrogenase, as potential molecular targets for B6. Both enzymes were recombinantly expressed and purified, and used for chemical validation. Indeed, B6 was able to inhibit both enzymes with IC(50) values in the micromolar range. The multifunctional profile was further characterized in experiments using permeabilized Trypanosoma brucei cells and mitochondrial cell fractions. It turned out that B6 was also able to generate oxygen radicals, a mechanism that may additionally contribute to its observed potent trypanocidal activity. CONCLUSIONS AND SIGNIFICANCE: Overall, B6 showed a multitarget mechanism of action, which provides a molecular explanation of its promising anti-trypanosomatid activity. Furthermore, the forward chemical genetics approach here applied may be viable in the molecular characterization of novel multitarget ligands

Discovery of sustainable drugs for neglected tropical diseases: cashew nutshell liquid (CNSL)-based hybrids target mitochondrial function and ATP production in Trypanosoma brucei.

In a search for effective and sustainable treatments for trypanosomiasis, we developed a library of hybrid compounds by merging the structural features of a previously synthesized quinone hit (4) with those of long‐chain phenolic constituents from cashew nut shell liquid (CNSL). CNSL is an agro‐waste product from cashew nut processing factories with great potential as a precursor for the production of drugs. The synthesized compounds were tested against Trypanosoma brucei brucei, including three multi‐drug resistant strains (B48, ISMR1, and aqp2/aqp3‐KO), T. congolense, and a human cell line (HFF). The most potent activity was found against T. b. brucei, the causative agent of African trypanosomiasis. Shorter‐chain derivatives were more active than the starting hit in parasite growth inhibition, displaying rapid trypanocidal activity with low micromolar EC50 values, but no discernable toxicity on human cell lines. Preliminary studies probing their mode of action on trypanosomes showed depletion of cellular ATP, followed by the depolarization of the mitochondrial membrane and ultrastructural damage to the mitochondrion. This was accompanied by the production of high levels of reactive oxygen species. We envisage that such hybrid compounds, obtained from renewable and inexpensive material, might be promising bio‐based, sustainable hits for anti‐trypanosomatid drug discovery