CircRNAs are here to stay: A perspective on the MLL recombinome

Chromosomal translocations harbored by cancer genomes are important oncogenic drivers. In MLL rearranged acute leukemia (MLLre) MLL/KMT2A fuses with over 90 partner genes. Mechanistic studies provided clues of MLL fusion protein leukemogenic potential, but models failed to fully recapitulate the disease. Recently, expression of oncogenic fusion circular RNAs (f-circ) by MLL-AF9 fusion was proven. This discovery, together with emerging data on the importance and diversity of circRNAs formed the incentive to study the circRNAs of the MLL recombinome. Through interactions with other RNAs, such as microRNAs, and with proteins, circRNAs regulate cellular processes also related to cancer development. CircRNAs can translate into functional peptides too. MLL and most of the 90 MLL translocation partners do express circRNAs and exploration of our RNA-seq dataset of sorted blood cell populations provided new data on alternative circular isoform generation and expression variability of circRNAs of the MLL recombinome. Further, we provided evidence that rearrangements of MLL and three of the main translocation partner genes can impact circRNA expression, supported also by preliminary observations in leukemic cells. The emerging picture underpins the view that circRNAs are worthwhile to be considered when studying MLLre leukemias and provides a new perspective on the impact of chromosomal translocations in cancer cells at large

Extracellular ATP is increased by release of ATP-loaded microparticles triggered by nutrient deprivation

Rationale: Caloric restriction improves the efficacy of anti-cancer therapy. This effect is largely dependent on the increase of the extracellular ATP concentration in the tumor microenvironment (TME). Pathways for ATP release triggered by nutrient deprivation are largely unknown. Methods: The extracellular ATP (eATP) concentration was in vivo measured in the tumor microenvironment of B16F10-inoculated C57Bl/6 mice with the pmeLuc probe. Alternatively, the pmeLuc-TG-mouse was used. Caloric restriction was in vivo induced with hydroxycitrate (HC). B16F10 melanoma cells or CT26 colon carcinoma cells were in vitro exposed to serum starvation to mimic nutrient deprivation. Energy metabolism was monitored by Seahorse. Microparticle release was measured by ultracentrifugation and by Nanosight. Results: Nutrient deprivation increases eATP release despite the dramatic inhibition of intracellular energy synthesis. Under these conditions oxidative phosphorylation was dramatically impaired, mitochondria fragmented and glycolysis and lactic acid release were enhanced. Nutrient deprivation stimulated a P2X7-dependent release of ATP-loaded, mitochondria-containing, microparticles as well as of naked mitochondria. Conclusions: Nutrient deprivation promotes a striking accumulation of eATP paralleled by a large release of ATP-laden microparticles and of naked mitochondria. This is likely to be a main mechanism driving the accumulation of eATP into the TME

Overview on electrical issues faced during the SPIDER experimental campaigns

SPIDER is the full-scale prototype of the ion source of the ITER Heating Neutral Beam Injector, where negative ions of Hydrogen or Deuterium are produced by a RF generated plasma and accelerated with a set of grids up to ~100 keV. The Power Supply System is composed of high voltage dc power supplies capable of handling frequent grid breakdowns, high current dc generators for the magnetic filter field and RF generators for the plasma generation. During the first 3 years of SPIDER operation different electrical issues were discovered, understood and addressed thanks to deep analyses of the experimental results supported by modelling activities. The paper gives an overview on the observed phenomena and relevant analyses to understand them, on the effectiveness of the short-term modifications provided to SPIDER to face the encountered issues and on the design principle of long-term solutions to be introduced during the currently ongoing long shutdown.Comment: 8 pages, 12 figures. Presented at SOFT 202

Designing of a cabin support for cableway

openProgettazione di un supporto cabina per funivie con verifica a fatic

Electrophysiologic stimulation improves myogenic potential of muscle precursor cells grown in a 3D collagen scaffold

The production of engineered three-dimensional (3D) skeletal muscle grafts holds promise for treatment of several diseases. An important factor in the development of such approach involves the capability of preserving myogenicity and regenerative potential during ex vivo culturing. We have previously shown that electrical stimulation of myogenic cells grown in monolayer could improve the differentiation process. Here we investigated the effect of exogenous electrical field, specifically designed to mimic part of the neuronal activity, on muscle precursor cells (MPCs) cultured within 3D collagen scaffolds. Our data showed that electric stimulation did not affect cell viability and increased by 65.6% the release rate of NOx, an early molecular activator of satellite cells in vivo. NOx release rate was decreased by an inhibitor of NO synthase, both in stimulated and non-stimulated cultures, confirming the endocrine origin of the measured NOx. Importantly, electrical stimulation also increased the expression of two myogenic markers, MyoD and desmin. We also carried out some preliminary experiments aimed at determining the biocompatibility of our seeded collagen scaffolds, implanting them in the tibialis anterior muscles of syngeneic mice. Ten days after transplantation, we could observe the formation of new myofibers both inside the scaffold and at the scaffold/muscle interface. Altogether, our findings indicate that electrical stimulation could be a new strategy for the effective 3D expansion of muscle precursor cells in vitro without losing myogenic potential and that 3D collagen matrices could be a promising tool for delivering myogenic cells in recipient muscle