Design, synthesis and molecular modeling studies of drug candidate compounds against prion diseases

Prion diseases are a group of invariably fatal disorders, for which there is no cure. Despite their rare incidence in humans, prion diseases have captured very large attention from the scientific community due to the unconventional mechanism by which they are transmitted.1 The central feature of prion diseases is the accumulation in the brain and some other tissues of the diseaseassociated PrPSc, which is derived from the host-encoded cellular PrPC.1 The conversion from a normal form (PrPC) to an infectious isoform (scrapie, PrPSc) is triggered by the interaction between PrPC-PrPSc,2 as well as protein-protein interaction (PPI).3...

EANM guideline for harmonisation on molar activity or specific activity of radiopharmaceuticals:impact on safety and imaging quality

Abstract This guideline on molar activity (Am) and specific activity (As) focusses on small molecules, peptides and macromolecules radiolabelled for diagnostic and therapeutic applications. In this guideline we describe the definition of Am and As, and how these measurements must be standardised and harmonised. Selected examples highlighting the importance of Am and As in imaging studies of saturable binding sites will be given, and the necessity of using appropriate materials and equipment will be discussed. Furthermore, common Am pitfalls and remedies are described. Finally, some aspects of Am in relation the emergence of a new generation of highly sensitive PET scanners will be discussed

Structure-driven discovery of α,γ-diketoacid inhibitors against UL89 Herpesvirus Terminase

Human cytomegalovirus (HCMV) is an opportunistic pathogen causing a variety of severe viral infections, including irreversible congenital disabilities. Nowadays, HCMV infection is treated by inhibiting the viral DNA polymerase. However, DNA polymerase inhibitors have several drawbacks. An alternative strategy is to use compounds against the packaging machinery or terminase complex, which is essential for viral replication. Our discovery that raltegravir (1), a human immunodeficiency virus drug, inhibits the nuclease function of UL89, one of the protein subunits of the complex, prompted us to further develop terminase inhibitors. On the basis of the structure of 1, a library of diketoacid (α,γ-DKA and β,δ-DKA) derivatives were synthesized and tested for UL89-C nuclease activity. The mode of action of α,γ-DKA derivatives on the UL89 active site was elucidated by using X-ray crystallography, molecular docking, and in vitro experiments. Our studies identified α,γ-DKA derivative 14 able to inhibit UL89 in vitro in the low micromolar range, making 14 an optimal candidate for further development and virus-infected cell assay

Deep ensemble learning and transfer learning methods for classification of senescent cells from nonlinear optical microscopy images

The success of chemotherapy and radiotherapy anti-cancer treatments can result in tumor suppression or senescence induction. Senescence was previously considered a favorable therapeutic outcome, until recent advancements in oncology research evidenced senescence as one of the culprits of cancer recurrence. Its detection requires multiple assays, and nonlinear optical (NLO) microscopy provides a solution for fast, non-invasive, and label-free detection of therapy-induced senescent cells. Here, we develop several deep learning architectures to perform binary classification between senescent and proliferating human cancer cells using NLO microscopy images and we compare their performances. As a result of our work, we demonstrate that the most performing approach is the one based on an ensemble classifier, that uses seven different pre-trained classification networks, taken from literature, with the addition of fully connected layers on top of their architectures. This approach achieves a classification accuracy of over 90%, showing the possibility of building an automatic, unbiased senescent cells image classifier starting from multimodal NLO microscopy data. Our results open the way to a deeper investigation of senescence classification via deep learning techniques with a potential application in clinical diagnosis

Radiosynthesis, Preclinical, and Clinical Positron Emission Tomography Studies of Carbon-11 Labeled Endogenous and Natural Exogenous Compounds

The presence of positron emission tomography (PET) centers at most major hospitals worldwide, along with the improvement of PET scanner sensitivity and the introduction of total body PET systems, has increased the interest in the PET tracer development using the short-lived radionuclides carbon-11. In the last few decades, methodological improvements and fully automated modules have allowed the development of carbon-11 tracers for clinical use. Radiolabeling natural compounds with carbon-11 by substituting one of the backbone carbons with the radionuclide has provided important information on the biochemistry of the authentic compounds and increased the understanding of their in vivo behavior in healthy and diseased states. The number of endogenous and natural compounds essential for human life is staggering, ranging from simple alcohols to vitamins and peptides. This review collates all the carbon-11 radiolabeled endogenous and natural exogenous compounds synthesised to date, including essential information on their radiochemistry methodologies and preclinical and clinical studies in healthy subjects

Noninvasive morpho-molecular imaging reveals early therapy-induced senescence in human cancer cells

Anticancer therapy screening in vitro identifies additional treatments and improves clinical outcomes. Systematically, although most tested cells respond to cues with apoptosis, an appreciable portion enters a senescent state, a critical condition potentially driving tumor resistance and relapse. Conventional screening protocols would strongly benefit from prompt identification and monitoring of therapy-induced senescent (TIS) cells in their native form. We combined complementary all-optical, label-free, and quantitative microscopy techniques, based on coherent Raman scattering, multiphoton absorption, and interferometry, to explore the early onset and progression of this phenotype, which has been understudied in unperturbed conditions. We identified TIS manifestations as early as 24 hours following treatment, consisting of substantial mitochondrial rearrangement and increase of volume and dry mass, followed by accumulation of lipid vesicles starting at 72 hours. This work holds the potential to affect anticancer treatment research, by offering a label-free, rapid, and accurate method to identify initial TIS in tumor cells

Full-Spectrum CARS Microscopy of Cells and Tissues with Ultrashort White-Light Continuum Pulses

Coherent anti-StokesRaman scattering (CARS) microscopyis an emergingnonlinear vibrational imaging technique that delivers label-free chemicalmaps of cells and tissues. In narrowband CARS, two spatiotemporallysuperimposed picosecond pulses, pump and Stokes, illuminate the sampleto interrogate a single vibrational mode. Broadband CARS (BCARS) combinesnarrowband pump pulses with broadband Stokes pulses to record broadvibrational spectra. Despite recent technological advancements, BCARSmicroscopes still struggle to image biological samples over the entireRaman-active region (400-3100 cm(-1)). Here,we demonstrate a robust BCARS platform that answers this need. Oursystem is based on a femtosecond ytterbium laser at a 1035 nm wavelengthand a 2 MHz repetition rate, which delivers high-energy pulses usedto produce broadband Stokes pulses by white-light continuum generationin a bulk YAG crystal. Combining such pulses, pre-compressed to sub-20fs duration, with narrowband pump pulses, we generate a CARS signalwith a high (<9 cm(-1)) spectral resolution inthe whole Raman-active window, exploiting both the two-color and three-colorexcitation mechanisms. Aided by an innovative post-processing pipeline,our microscope allows us to perform high-speed (approximate to 1 ms pixeldwell time) imaging over a large field of view, identifying the mainchemical compounds in cancer cells and discriminating tumorous fromhealthy regions in liver slices of mouse models, paving the way forapplications in histopathological settings

The concept of privileged structures in rational drug design:focus on acridine and quinoline scaffolds in neurodegenerative and protozoan diseases

Introduction: For nearly 20 years, privileged structures have offered an optimal source of core scaffolds and capping fragments for the design of combinatorial libraries directed at a broad spectrum of targets. From describing structures promiscuous within a given target family, the concept has evolved to include frameworks that can modulate proteins lacking a strict target class relation. Areas covered: Based on a literature search from 2000 to 2010, we discuss how two privileged motifs, quinolines and acridines, are particularly recurrent in compounds active against two quite different pathologies, neurodegenerative and protozoan diseases. Expert opinion: As privileged structures, quinolines and acridines could improve the productivity of drug discovery projects in the field of neurodegenerative and protozoan diseases. They could be particularly relevant for protozoan diseases because of the importance of cost-effective strategies and less stringent intellectual property concerns. Furthermore, because of their inherent affinity for various targets, privileged structures could offer a viable starting point in the search for novel multi-target ligands. Finally, from a broader perspective, they can serve as effective probes for investigating unknown but interrelated mechanisms of action