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Early diagnosis is one of the most important factors in determining the prognosis in cancer. Sensitive detection and quantification of tumour-specific biomarkers have the potential to improve significantly our diagnostic capability. Here, we introduce a triggerable aptamer-based nanostructure based on an oligonucleotide/gold nanoparticle architecture that selectively disassembles in the presence of the biomarker of interest; its optimization is based also on in-silico determination of the aptamer nucleotides interactions with the protein of interest. We demonstrate this scheme for the case of Prostate Specific Membrane Antigen (PSMA) and PSMA derived from PSMA-positive exosomes. We tested the disassembly of the system by diameter and count rate measurements in dynamic light scattering, and by inspection of its plasmon resonance shift, upon addition of PSMA, finding appreciable differences down to the sub-picomolar range; this points towards the possibility that this approach may lead to sensors competitive with diagnostic biochemical assays that require enzymatic amplification. More generally, this scheme has the potential to be applied to a broad range of pathologies with specific identified biomarkers., (© 2023. The Author(s).)

In proliferating multipotent retinal progenitors, transcription factors dynamics set the fate of postmitotic daughter cells, but postmitotic cell fate plasticity driven by extrinsic factors remains controversial. Transcriptome analysis reveals the concurrent expression by postmitotic rod precursors of genes critical for the Müller glia cell fate, which are rarely generated from terminally-dividing progenitors as a pair with rod precursors. By combining gene expression and functional characterisation in single cultured rod precursors, we identified a time-restricted window where increasing cell culture density switches off the expression of genes critical for Müller glial cells. Intriguingly, rod precursors in low cell culture density maintain the expression of genes of rod and glial cell fate and develop a mixed rod/Muller glial cells electrophysiological fingerprint, revealing rods derailment toward a hybrid rod-glial phenotype. The notion of cell culture density as an extrinsic factor critical for preventing rod-fated cells diversion toward a hybrid cell state may explain the occurrence of hybrid rod/MG cells in the adult retina and provide a strategy to improve engraftment yield in regenerative approaches to retinal degenerative disease by stabilising the fate of grafted rod precursors., (© 2023. The Author(s).)

Molecular markers are suggested to improve the diagnostic and prognostic accuracy in patients with coronary artery disease (CAD) beyond current clinical scores based on age, gender, symptoms and traditional risk factors. In this context, plasma lipids are emerging as predictors of both plaque composition and risk of future events. We aim to identify plasma lipid biomarkers associated to CAD indexes of stenosis severity, plaque lipid content and a comprensive score of CAD extent and its risk. We used a simple high performance liquid chromatography-tandem mass spectrometry method to identify 69 plasma lipids in 132 subjects referred to Coronary Computed Tomography Angiography (CCTA) for suspected CAD, all under statin treatment. Patients were stratified in groups using three different CCTA-based annotations: CTA-risk score, lipid plaque prevalence (LPP) ratio and the coronary artery disease-reporting and data system (CAD-RADS). We identified a common set of lipid biomarkers composed of 7 sphingomyelins and 3 phosphatidylethanolamines, which discriminates between high risk CAD patients and controls regardless of the CAD annotations used (CTA score, LPP ratio, or CAD-RADS). These results highlight the potential of circulating lipids as biomarkers of stenosis severity, non calcified plaque composition and overall plaque risk of events.

Biological samples are mainly composed of elements with a low atomic number which show a relatively low electron scattering power. For Transmission Electron Microscopy analysis, biological samples are generally embedded in resins, which allow thin sectioning of the specimen. Embedding resins are also composed by light atoms, thus the contrast difference between the biological sample and the surrounding resin is minimal. Due to that reason in the last decades, several staining solutions and approaches, performed with heavy metal salts, have been developed with the purpose of enhancing both the intrinsic sample contrast and the differences between the sample and resin. The best staining was achieved with the uranyl acetate (UA) solution, which has been the election method for the study of morphology in biological samples. More recently several alternatives for UA have been proposed to get rid of its radiogenic issues, but to date none of these solutions has achieved efficiencies comparable to UA. In this work, we propose a different staining solution (X Solution or X SOL), characterized by lanthanide polyoxometalates (LnPOMs) as heavy atoms source, which could be used alternatively to UA in negative staining (NS), in en bloc staining, and post sectioning staining (PSS) of biological samples. Furthermore, we show an extensive chemical characterization of the LnPOM species present in the solution and the detailed work for its final formulation, which brought remarkable results, and even better performances than UA.

The classical view of nerve growth factor (NGF) action in the nervous system is linked to its retrograde axonal transport. However, almost nothing is known on the trafficking properties of its unprocessed precursor proNGF, characterized by different and generally opposite biological functions with respect to its mature counterpart. Here we developed a strategy to fluorolabel both purified precursor and mature neurotrophins (NTs) with a controlled stoichiometry and insertion site. Using a single particle tracking approach, we characterized the axonal transport of proNGF versus mature NGF in living dorsal root ganglion neurons grown in compartmentalized microfluidic devices. We demonstrate that proNGF is retrogradely transported as NGF, but with a lower flux and a different distribution of numbers of neurotrophins per vesicle. Moreover, exploiting a dual-color labelling technique, we analysed the transport of both NT forms when simultaneously administered to the axon tips.

Peptides that translocate spontaneously across cell membranes could transform the field of drug delivery by enabling the transport of otherwise membrane-impermeant molecules into cells. In this regard, a 9-aminoacid-long motif (representative sequence: PLIYLRLLR, hereafter Translocating Motif 9, TM9) that spontaneously translocates across membranes while carrying a polar dye was recently identified by high-throughput screening. Here we investigate its transport properties by a combination of in cuvette physico-chemical assays, rational mutagenesis, live-cell confocal imaging and fluorescence correlation spectroscopy measurements. We unveil TM9 ability to self-aggregate in a concentration-dependent manner and demonstrate that peptide self-aggregation is a necessary--yet not sufficient--step for effective membrane translocation. Furthermore we show that membrane crossing can occur with apolar payloads while it is completely inhibited by polar ones. These findings are discussed and compared to previous reports. The present results impose a careful rethinking of this class of sequences as direct-translocation vectors suitable for delivery purposes.