CHARACTERIZATION OF YB-1 AS A NOVEL STRESS BIOMARKER AND PARACRINE SIGNALING POLYPEPTIDE

Cell signalling is the complex network of connections between cells and inside the single cell. Protein trafficking is deeply involved in cell signalling. Different proteins are ordered in clusters of receptors of extracellular signals, transducers, sensors and biological response effectors. Together, they are arranged in molecular pathways that are relevant for maintenance of cell homeostasis. Protein secretion is a relevant component of eukaryotic cell signalling. The prototype cold-shock Y-box binding protein 1 (YB-1) is a multifunctional protein which regulates a variety of fundamental biological processes. Recently YB-1 has been found in human extracellular fluids and shown to be secreted by different cell types. This PhD project is focused on YB-1 protein secretion to investigate on its role as a potential paracrine signal to elicit changes or responses in nearby cells, altering their behaviour. During the first part of the project I focused on stimuli and conditions triggering YB-1 secretion. Low amounts of extracellular YB-1 are released by HEK293T cells in physiological condition. Interestingly, I found that YB-1 secretion was enhanced following oxidative insults. Secreted YB-1 protein was purified and analysed by mass spectrometry to confirm its identity. In parallel, I verified the assembly of YB-1 in stress granules (SGs), cytoplasmic foci where untranslated mRNAs are sorted or processed for reinitiation, degradation, or packaging into mRNPs. To understand the mechanism beneath YB-1 secretion and uptake by receiving cells, I tried several experimental approaches; among them the production and characterization of a stable HEK293T cell line expressing a YB-1-GFP fusion protein. The properties of this cell line as a stress biosensor were evaluated. The second part of the project was devoted to the production of purified recombinant human YB-1 (rYB-1) in bacterial host. In parallel I produced enriched fractions of YB-1 from HEK293T cell culture medium (CCM-YB-1). I found that both CCM-YB-1 and rYB-1 have anti-proliferative activity on receiving cells. Both forms of YB-1 protein were effective on different recipient cell lines, including HaCaT cells. In particular, inhibition of human keratinocytes proliferation by extracellular YB-1 was associated to a G2/M cell cycle arrest, induction of p21WAF and reduction of Np63 protein level. The obtained results suggest that sustained release of full length YB-1 protein or YB-1 derived peptides, by stress stimuli acts as paracrine/autocrine signal stimulating cell cycle arrest. Finally, I spent six months of my PhD at the Institute of Toxicology and Genetics (ITG-KIT), in Karlsruhe, Germany, where I had the opportunity to study the behaviour of the evolutionarily conserved YB-1 in zebrafish (Danio rerio), one of the most versatile genetic models for environmental studies. Unexpectedly, I found that zebrafish cells assemble YB-1 positive aggregates only in response to heat, but not oxidative stress or copper treatment. YB-1-positive aggregates were confirmed as SGs as they contained the G3BP1 protein, a well assessed SG marker in mammalian. I found that zfYB-1 gene silencing compromised cell viability under heat shock, but not in normal conditions highlighting the essential role played by YB-1 in cell survival following heat shock. My findings point to a fundamental role of YB-1 as a valuable biomarker for thermal stress

Executive functions in Alzheimer disease. A systematic review

Alzheimer's disease is a severe irreversible syndrome, characterized by a slow and progressive cognitive decline that interferes with the standard instrumental and essential functions of daily life. Promptly identifying the impairment of particular cognitive functions could be a fundamental condition to limit, through preventive or therapeutic interventions, the functional damages found in this degenerative dementia. This study aims to analyse, through a systematic review of the studies, the sensitivity of four experimental paradigms (Wisconsin Card Sorting Test, Stroop Task, Go/No-Go Task, and Flanker Task) considered as golden standard instruments for executive functions assessment in elderly subjects affected by Alzheimer dementia. This review was carried out according to the PRISMA method. Forty-five studies comparing the executive performance of patients with Alzheimer's dementia (diagnosed according to different classification criteria for dementia) and healthy elderly patients both over the age of sixty, were selected. For the research, PubMed, PsycINFO, PsycArticles databases were used. The study highlighted the importance of using standard protocols to evaluate executive dysfunction in Alzheimer's disease. The Stroop task allows discriminating better between healthy and pathological agin

Machine dependence and reproducibility for coupled climate simulations: the HadGEM3-GC3.1 CMIP Preindustrial simulation

When the same weather or climate simulation is run on different high-performance computing (HPC) platforms, model outputs may not be identical for a given initial condition. While the role of HPC platforms in delivering better climate projections is to some extent discussed in the literature, attention is mainly focused on scalability and performance rather than on the impact of machine-dependent processes on the numerical solution. Here we investigate the behaviour of the Preindustrial (PI) simulation prepared by the UK Met Office for the forthcoming CMIP6 (Coupled Model Intercomparison Project Phase 6) under different computing environments. Discrepancies between the means of key climate variables were analysed at different timescales, from decadal to centennial. We found that for the two simulations to be statistically indistinguishable, a 200-year averaging period must be used for the analysis of the results. Thus, constant-forcing climate simulations using the HadGEM3-GC3.1 model are reproducible on different HPC platforms provided that a sufficiently long duration of simulation is used. In regions where El Niño–Southern Oscillation (ENSO) teleconnection patterns were detected, we found large sea surface temperature and sea ice concentration differences on centennial timescales. This indicates that a 100-year constant-forcing climate simulation may not be long enough to adequately capture the internal variability of the HadGEM3-GC3.1 model, despite this being the minimum simulation length recommended by CMIP6 protocols for many MIP (Model Intercomparison Project) experiments. On the basis of our findings, we recommend a minimum simulation length of 200 years whenever possible

A new species of Anthemis sect. Hiorthia (Asteraceae) from SE Sicily

A new species of Anthemis sect. Hiorthia (Asteraceae) is described from Sicily. This taxon, named A. pignattiorum, is confined to a restricted area of the Hyblaean territory (SE Sicily), in the Natural Reserve of Cava Grande (Cassibile, Siracuse), where it takes shelter on carbonate rocky habitat and participates, with other Sicilian endemic taxa, to the composition of a termophilous chasmophytic community (Putorio calabricae–Micromerietum microphyllae)

Isolated liver transplantation for treatment of liver failure secondary to intestinal failure

Intestinal Failure is a permanent loss of digestive and absorptive functions as a consequence of short bowel syndrome and/or other primary intestinal conditions. Patients with intestinal failure (IF) require long term parenteral nutrition to survive. The only alternative to parenteral nutrition is intestinal transplantation which still entails high mortality. Children with intestinal failure on parenteral nutrition may develop liver failure (LF), as a consequence of central line infections and other conditions. In children with both irreversible IF and LF a combined transplantation is generally considered. Despite low survival rate, combined liver/intestine transplantation is associated to better intestinal graft survival and lower incidence and severity of rejection compared to isolated small bowel transplantation. Recently, isolated liver transplantation was proposed in children with IF and LF. This procedure may have a higher survival probability compared to isolated intestinal transplant, it may allow progressive weaning from PN in children in whom the remnant intestine has the potential for adaptation and offer a timely solution in children for whom intestinal graft is not immediately available. This innovative approach may prove a better option compared to combined transplantation in both the short and long ter

Phytopharmacological strategies in the management of type 2 diabetes Mellitus

Type 2 Diabetes Mellitus (T2DM) is a chronic disease which corresponds to 90% of the worldwide cases of diabetes, mainly due to epigenetic factors such as unhealthy lifestyles. First line therapeutic approaches are based on lifestyle changes, most of the time complemented with medication mostly associated with several side e ects and high costs. As a result, the scientific community is constantly working for the discovery and development of natural therapeutic strategies that provide lower financial impact and minimize side e ects. This review focus on these nature-based therapeutic strategies for prevention and control of T2DM, with a special emphasis on natural compounds that present pharmacological activity as dipeptidyl peptidase-4 (DPP4), alpha-amylase, alpha-glucosidase, lipase, and protein tyrosine phosphatase 1B (PTP1B) inhibitors.info:eu-repo/semantics/publishedVersio

First Insights on the Karyotype Diversification of the Endemic Malagasy Leaf-Toed Geckos (Squamata: Gekkonidae: Uroplatus)

We provide here the first karyotype description of eight Uroplatus species and a characterization of their chromosomal diversity. We performed a molecular taxonomic assessment of several Uroplatus samples using the mitochondrial 12S marker and a comparative cytogenetic analysis with standard karyotyping, silver staining (Ag-NOR) and sequential C-banding + Giemsa, +Chromomycin A3 (CMA3), +4',6-diamidino-2-phenylindole (DAPI). We found chromosomal variability in terms of chromosome number (2n = 34-38), heterochromatin composition and number and localization of loci or Nucleolar Organizer Regions (NORs) (alternatively on the 2nd, 6th, 10th or 16th pair). Chromosome morphology is almost constant, with karyotypes composed of acrocentric chromosomes, gradually decreasing in length. C-banding evidenced a general low content of heterochromatin, mostly localized on pericentromeric and telomeric regions. Centromeric bands varied among the species studied, resulting in CMA3 positive and DAPI negative or positive to both fluorochromes. We also provide evidence of a first putative heteromorphic sex chromosome system in the genus. In fact, in U. alluaudi the 10th pair was highly heteromorphic, with a metacentric, largely heterochromatic W chromosome, which was much bigger than the Z. We propose an evolutionary scenario of chromosome reduction from 2n = 38 to 2n = 34, by means of translocations of microchromosomes on larger chromosomes (often involving the NOR-bearing microchromosomes). Adding our data to those available from the literature, we show that similar processes characterized the evolutionary radiation of a larger gecko clade. Finally, we hypothesize that sex chromosome diversification occurred independently in different genera

Evolutionary and Genomic Diversity of True Polyploidy in Tetrapods

: True polyploid organisms have more than two chromosome sets in their somatic and germline cells. Polyploidy is a major evolutionary force and has played a significant role in the early genomic evolution of plants, different invertebrate taxa, chordates, and teleosts. However, the contribution of polyploidy to the generation of new genomic, ecological, and species diversity in tetrapods has traditionally been underestimated. Indeed, polyploidy represents an important pathway of genomic evolution, occurring in most higher-taxa tetrapods and displaying a variety of different forms, genomic configurations, and biological implications. Herein, we report and discuss the available information on the different origins and evolutionary and ecological significance of true polyploidy in tetrapods. Among the main tetrapod lineages, modern amphibians have an unparalleled diversity of polyploids and, until recently, they were considered to be the only vertebrates with closely related diploid and polyploid bisexual species or populations. In reptiles, polyploidy was thought to be restricted to squamates and associated with parthenogenesis. In birds and mammals, true polyploidy has generally been considered absent (non-tolerated). These views are being changed due to an accumulation of new data, and the impact as well as the different evolutionary and ecological implications of polyploidy in tetrapods, deserve a broader evaluation