The High Mobility Group A1 (HMGA1) Chromatin Architectural Factor Modulates Nuclear Stiffness in Breast Cancer Cells

13siPlasticity is an essential condition for cancer cells to invade surrounding tissues. The nucleus is the most rigid cellular organelle and it undergoes substantial deformations to get through environmental constrictions. Nuclear stiffness mostly depends on the nuclear lamina and chromatin, which in turn might be affected by nuclear architectural proteins. Among these is the HMGA1 (High Mobility Group A1) protein, a factor that plays a causal role in neoplastic transformation and that is able to disentangle heterochromatic domains by H1 displacement. Here we made use of atomic force microscopy to analyze the stiffness of breast cancer cellular models in which we modulated HMGA1 expression to investigate its role in regulating nuclear plasticity. Since histone H1 is the main modulator of chromatin structure and HMGA1 is a well-established histone H1 competitor, we correlated HMGA1 expression and cellular stiffness with histone H1 expression level, post-translational modifications, and nuclear distribution. Our results showed that HMGA1 expression level correlates with nuclear stiffness, is associated to histone H1 phosphorylation status, and alters both histone H1 chromatin distribution and expression. These data suggest that HMGA1 might promote chromatin relaxation through a histone H1-mediated mechanism strongly impacting on the invasiveness of cancer cells-openopenSenigagliesi B, Penzo C, Severino LU, Maraspini R, Petrosino S, Morales-Navarrete H, Pobega E, Ambrosetti E, Parisse P, Pegoraro S, Manfioletti G, Casalis L, Sgarra RSenigagliesi, Beatrice; Penzo, C; Severino, Lu; Maraspini, R; Petrosino, Sara; Morales-Navarrete, H; Pobega, E; Ambrosetti, E; Parisse, P; Pegoraro, S; Manfioletti, G; Casalis, L; Sgarra,

Electro-chemical deposition of zinc oxide nanostructures by using two electrodes

One of the most viable ways to grow nanostructures is electro deposition. However, most electrodeposited samples are obtained by three-electrode electrochemical cell. We successfully use a much simpler two-electrode cell to grow different ZnO nanostructures from common chemical reagents. Concentration, pH of the electrolytes and growth parameters like potentials at the electrodes, are tailored to allow fast growth without complexity. Morphology and surface roughness are investigated by Scanning Electron and Air Force Microscopy (SEM and AFM) respectively, crystal structure by X-Ray Diffraction measurements (XRD) and ZnO stoichiometry by core level photoemission spectroscopy (XPS)

Defined \u3b1-synuclein prion-like molecular assemblies spreading in cell culture

BACKGROUND: \u3b1-Synuclein (\u3b1-syn) plays a central role in the pathogenesis of synucleinopathies, a group of neurodegenerative disorders that includes Parkinson disease, dementia with Lewy bodies and multiple system atrophy. Several findings from cell culture and mouse experiments suggest intercellular \u3b1-syn transfer. RESULTS: Through a methodology used to obtain synthetic mammalian prions, we tested whether recombinant human \u3b1-syn amyloids can promote prion-like accumulation in neuronal cell lines in vitro. A single exposure to amyloid fibrils of human \u3b1-syn was sufficient to induce aggregation of endogenous \u3b1-syn in human neuroblastoma SH-SY5Y cells. Remarkably, endogenous wild-type \u3b1-syn was sufficient for the formation of these aggregates, and overexpression of the protein was not required. CONCLUSIONS: Our results provide compelling evidence that endogenous \u3b1-syn can accumulate in cell culture after a single exposure to exogenous \u3b1-syn short amyloid fibrils. Importantly, using \u3b1-syn short amyloid fibrils as seed, endogenous \u3b1-syn aggregates and accumulates over several passages in cell culture, providing an excellent tool for potential therapeutic screening of pathogenic \u3b1-syn aggregates

Computational Evolution of Beta-2-Microglobulin Binding Peptides for Nanopatterned Surface Sensors

The bottom-up design of smart nanodevices largely depends on the accuracy by which each of the inherent nanometric components can be functionally designed with predictive methods. Here, we present a rationally designed, self-assembled nanochip capable of capturing a target protein by means of pre-selected binding sites. The sensing elements comprise computationally evolved peptides, designed to target an arbitrarily selected binding site on the surface of beta-2-Microglobulin (β2m), a globular protein that lacks well-defined pockets. The nanopatterned surface was generated by an atomic force microscopy (AFM)-based, tip force-driven nanolithography technique termed nanografting to construct laterally confined self-assembled nanopatches of single stranded (ss)DNA. These were subsequently associated with an ssDNA–peptide conjugate by means of DNA-directed immobilization, therefore allowing control of the peptide’s spatial orientation. We characterized the sensitivity of such peptide-containing systems against β2m in solution by means of AFM-based differential topographic imaging and surface plasmon resonance (SPR) spectroscopy. Our results show that the confined peptides are capable of specifically capturing β2m from the surface–liquid interface with micromolar affinity, hence providing a viable proof-of-concept for our approach to peptide design

Influence of steps on the tilting and adsorption dynamics of ordered Pn films on vicinal Ag(111) surfaces

Here we present a structural study of pentacene (Pn) thin films on vicinal Ag(111) surfaces by He atom diffraction measurements and density functional theory (DFT) calculations supplemented with van der Waals (vdW) interactions. Our He atom diffraction results suggest initial adsorption at the step edges evidenced by initial slow specular reflection intensity decay rate as a function of Pn deposition time. In parallel with the experimental findings, our DFT+vdW calculations predict the step edges as the most stable adsorption site on the surface. An isolated molecule adsorbs as tilted on the step edge with a binding energy of 1.4 eV. In addition, a complete monolayer (ML) with pentacenes flat on the terraces and tilted only at the step edges is found to be more stable than one with all lying flat or tilted molecules, which in turn influences multilayers. Hence our results suggest that step edges can trap Pn molecules and act as nucleation sites for the growth of ordered thin films with a crystal structure similar to that of bulk Pn.Comment: 4 pages, 4 figures, 1 tabl

Transparent carbon nanotubes promote the outgrowth of enthorino-dentate projections in lesioned organ slice cultures

The increasing engineering of carbon-based nanomaterials as components of neuro-regenerative interfaces is motivated by their dimensional compatibility with subcellular compartments of excitable cells, such as axons and synapses. In neuroscience applications, carbon nanotubes (CNTs) have been used to improve electronic device performance by exploiting their physical properties. Besides, when manufactured to interface neuronal networks formation in vitro, CNT carpets have shown their unique ability to potentiate synaptic networks formation and function. Due to the low optical transparency of CNTs films, further developments of these materials in neural prosthesis fabrication or in implementing interfacing devices to be paired with in vivo imaging or in vitro optogenetic approaches are currently limited. In the present work, we exploit a new method to fabricate CNTs by growing them on a fused silica surface, which results in a transparent CNT-based substrate (tCNTs). We show that tCNTs favour dissociated primary neurons network formation and function, an effect comparable to the one observed for their dark counterparts. We further adopt tCNTs to support the growth of intact or lesioned Entorhinal-Hippocampal Complex organotypic cultures (EHCs). Through immunocytochemistry and electrophysiological field potential recordings, we show here that tCNTs platforms are suitable substrates for the growth of EHCs and we unmask their ability to significantly increase the signal synchronization and fibre sprouting between the cortex and the hippocampus with respect to Controls. tCNTs transparency and ability to enhance recovery of lesioned brain cultures, make them optimal candidates to implement implantable devices in regenerative medicine and tissue engineering. This article is protected by copyright. All rights reserved