Investigation of HNCO adsorption and hydrolysis on Fe-ZSM5

The adsorption of HNCO on Fe-ZSM5 was investigated in detail by DRIFT spectroscopy and compared to the adsorption on H-ZSM5, Al₂O₃, SiO₂, Fe₂O₃/Al₂O₃ and Fe₂O₃/SiO₂. At 150 °C, HNCO adsorbs dissociatively on Fe-ZSM5 producing principally isocyanate species (–NCO) adsorbed on Al and Fe sites. In the presence of water the hydrolysis of the –NCO groups to NH₃ was observed. Comparison of the DRIFT results with measurements of the catalytic activity of coated cordierite monoliths suggests that –NCO groups are likely intermediate species in the hydrolysis of HNCO over Fe-ZSM5.     

Determination of protein structure and dynamics combining immune algorithms and pattern search methods

Natural proteins quickly fold into a complicated three-dimensional structure. Evolutionary algorithms have been used to predict the native structure with the lowest energy conformation of the primary sequence of a given protein. Successful structure prediction requires a free energy function sufficiently close to the true potential for the native state, as well as a method for exploring the conformational space. Protein structure prediction is a challenging problem because current potential functions have limited accuracy and the conformational space is vast. In this work, we show an innovative approach to the protein folding (PF) problem based on an hybrid Immune Algorithm (IMMALG) and a quasi-Newton method starting from a population of promising protein conformations created by the global optimizer DIRECT. The new method has been tested on Met-Enkephelin peptide, which is a paradigmatic example of multiple–minima problem, 1POLY, 1ROP and the three helix protein 1BDC. DIRECT produces an initial population of promising candidate solutions within a potentially optimal rectangle for the funnel landscape of the PF problem. Hence, IMMALG starts from a population of promising protein conformations created by the global optimizer DIRECT. The experimental results show that such a multistage approach is a competitive and effective search method in the conformational search space of real proteins, in terms of solution quality and computational cost comparing the results of the current state-of-art algorithms.     

Magneto‐Plasmonic Au‐Fe Alloy Nanoparticles Designed for Multimodal SERS‐MRI‐CT Imaging

Diagnostic approaches based on multimodal imaging are needed for accurate selection of the therapeutic regimens in several diseases, although the dose of administered contrast drugs must be reduced to minimize side effects. Therefore, large efforts are deployed in the development of multimodal contrast agents (MCAs) that permit the complementary visualization of the same diseased area with different sensitivity and different spatial resolution by applying multiple diagnostic techniques. Ideally, MCAs should also allow imaging of diseased tissues with high spatial resolution during surgical interventions. Here a new system based on multifunctional Au‐Fe alloy nanoparticles designed to satisfy the main requirements of an ideal MCA is reported and their biocompatibility and imaging capability are described. The MCAs show easy and versatile surface conjugation with thiolated molecules, magnetic resonance imaging (MRI) and computed X‐ray tomography (CT) signals for anatomical and physiological information (i.e., diagnostic and prognostic imaging), large Raman signals amplified by surface enhanced Raman scattering (SERS) for high sensitivity and high resolution intrasurgical imaging, biocompatibility, exploitability for in vivo use and capability of selective accumulation in tumors by enhanced permeability and retention effect. Taken together, these results show that Au‐Fe nanoalloys are excellent candidates as multimodal MRI‐CT‐SERS imaging agents.     

Hypoxia Enhances the Expression of RNASET2 in Human Monocyte-Derived Dendritic Cells: Role of PI3K/AKT Pathway

Hypoxia is a key component of the tumor microenvironment (TME) and promotes not only tumor growth and metastasis, but also negatively affects infiltrating immune cells by impairing host immunity. Dendritic cells (DCs) are the most potent antigen-presenting cells and their biology is weakened in the TME in many ways, including the modulation of their viability. RNASET2 belongs to the T2 family of extracellular ribonucleases and, besides its nuclease activity, it exerts many additional functions. Indeed, RNASET2 is involved in several human pathologies, including cancer, and it is functionally relevant in the TME. RNASET2 functions are not restricted to cancer cells and its expression could be relevant also in other cell types which are important players in the TME, including DCs. Therefore, this study aimed to unravel the effect of hypoxia (2% O₂) on the expression of RNASET2 in DCs. Here, we showed that hypoxia enhanced the expression and secretion of RNASET2 in human monocyte-derived DCs. This paralleled the HIF-1α accumulation and HIF-dependent and -independent signaling, which are associated with DCs’ survival/autophagy/apoptosis. RNASET2 expression, under hypoxia, was regulated by the PI3K/AKT pathway and was almost completely abolished by TLR4 ligand, LPS. Taken together, these results highlight how hypoxia- dependent and -independent pathways shape RNASET2 expression in DCs, with new perspectives on its implication for TME and, therefore, in anti-tumor immunity.     

Design and Synthesis of Fluorescent Methylphenidate Analogues for a FRET-Based Assay of Synapsin III Binding

We previously described synapsin III (Syn III) as a synaptic phosphoprotein that controls dopamine release in cooperation with α-synuclein (aSyn). Moreover, we found that in Parkinson's disease (PD), Syn III also participates in aSyn aggregation and toxicity. Our recent observations point to threo-methylphenidate (MPH), a monoamine re-uptake inhibitor that efficiently counteracts the freezing-gait characteristic of advanced PD, as a ligand for Syn III. We have designed and synthesised two different fluorescently labelled MPH derivatives, one with Rhodamine Red (RHOD) and one with 5-carboxytetramethylrhodamine (TAMRA), to be used for assessing MPH binding to Syn III by FRET. TAMRA-MPH exhibited the ideal characteristics to be used as a FRET acceptor, as it was able to enter into the SK-N-SH cells and could interact specifically with human green fluorescent protein (GFP)-tagged Syn III but not with GFP alone. Moreover, the uptake of TAMRA-MPH and co-localization with Syn III was also observed in primary mesencephalic neurons. These findings support that MPH is a Syn III ligand and that TAMRA-conjugated drug molecules might be valuable tools to study drug-ligand interactions by FRET or to detect Syn III in cytological and histological samples.     

Phosphodiesterases and Compartmentation of cAMP and cGMP Signaling in Regulation of Cardiac Contractility in Normal and Failing Hearts

Cardiac contractility is regulated by several neural, hormonal, paracrine, and autocrine factors. Amongst these, signaling through β-adrenergic and serotonin receptors generates the second messenger cyclic AMP (cAMP), whereas activation of natriuretic peptide receptors and soluble guanylyl cyclases generates cyclic GMP (cGMP). Both cyclic nucleotides regulate cardiac contractility through several mechanisms. Phosphodiesterases (PDEs) are enzymes that degrade cAMP and cGMP and therefore determine the dynamics of their downstream effects. In addition, the intracellular localization of the different PDEs may contribute to regulation of compartmented signaling of cAMP and cGMP. In this review, we will focus on the role of PDEs in regulating contractility and evaluate changes in heart failure.