Modification of Cellular DNA by Synthetic Aziridinomitosenes

Two synthetic aziridinomitosenes (AZMs), Me-AZM and H-AZM, structurally related to mitomycin C (MC) were evaluated for their anticancer activity against six cancer cell lines (HeLa, Jurkat, T47D, HepG2, HL-60, and HuT-78) and tested for their DNA-modifying abilities in Jurkat cells. Cytotoxicity assays showed that Me-AZM is up to 72-fold and 520-fold more potent than MC and H-AZM, respectively. Me-AZM also demonstrated increased DNA modification over MC and H-AZM in alkaline COMET and Hoechst fluorescence assays that measured crosslinks in cellular DNA. Me-AZM and H-AZM treatment of Jurkat cells was found to sponsor significant DNA-protein crosslinks using a K-SDS assay. The results clearly indicate that the AZM C6/C7 substitution pattern plays an important role in drug activity and supports both DNA-DNA and DNA-protein adduct formation as mechanisms for inducing cytotoxic effects

Tubular composite scaffolds produced via Diffusion Induced Phase Separation (DIPS) as a shaping strategy for anterior cruciate ligaments reconstruction

Injuries of tendons and ligaments are common, especially among the young population. Anterior cruciate ligament (ACL) injuries do not heal due to its limited vascularization and hence, surgical intervention is usually required. The ideal scaffold for ligament tissue engineering (TE) should be biocompatible and possess mechanical and functional characteristics comparable to the native ACL. The Diffusion Induced Phase Separation (DIPS) technique allows the preparation of homogenous porous tubular scaffold with micro-pores using a rather simple procedure. Composites based on biodegradable polymers and bioglass have attracted much attention in tissue reconstruction and repair because of their biological and physicochemical advantages. In this work a new approach in ACL TE will be proposed focussing on the development of a suitable technique for in vitro seeding of lapine ACL fibroblasts into tubular-shaped instructive Poly-lactic-acid (PLLA) scaffolds, supplemented or not with bioglass (BG) 1393, produced via DIPS. Tubular composite scaffold (diameters: 1.2 and 2 mm, +/- BG) were obtained through a dip coating around a cylindrical support followed by a DIPS. An 8%wt PLLA/dioxane solution was prepared with 5%wt of BG-1393 as filler. Preliminary in vitro cell culture trials were carried out by seeding lapine ACL fibroblasts inside the scaffolds (2 cm as length) employing different seeding strategies in order to find the best way that allows to obtain a homogeneous fibroblast distribution inside the tubes. (1) First trials consisted in the inoculating of the cell suspension inside the tubes and maintaining them in dynamical culture. (2) The second one was done by suspending the cells in a fibrin gel polymerized within the tubes by using of thrombin. (3) The third approach was carried out by using cell spheroids (three-dimensional self-assembled cell agglomerates). Cell attachment, viability and morphology were examined by live-death and Hematoxylin/Eosin stainings after 1, 7, 14 d and vimentin immunolabelings (7 d). Scanning electron microscopical analysis revealed that the internal surface of the tubes was homogeneously structured with micropores sized around 5 µm and a mean thickness of the wall of 60 µm. The results showed cell adhesion to the wall of the tubes with all seeding techniques applied even though with fibrin gel it was more homogenous. Furthermore, colonized areas expanded with culture time and the majority of cell survived irrespectively of seeding techniques. (1) In inoculation phase, many cells left the scaffold and attached on the plate. Even after the dynamic culture (rotating device) most cells covered only half the tube inner surface. (2) In the second trial, a fibrin gel was used to achieve a homogenous cell distribution during seeding. In the early stage (48 h) cells remained captured inside the fibrin, but after 7 d they become elongated and migrated from the fibrin to the inner tube surface forming a compact cell layer. So, the fibrin appears helpful to achieve an immediate high cell seeding efficiency and an almost homogeneous cell distribution inside the tubes. (3) Although using the spheroid technique the scaffold internal surface was not homogeneously colonized with cells, after 7 d cell migration to the inner scaffold surface from the attaching spheroids could be observed. In longitudinal sections cells were elongated like typical ligament fibroblasts parallel to the longitudinal tube axis. Therefore, it can be affirmed that employment of tubular scaffolds produced by DIPS could be a promising approach of ligament TE. In the future, it would be interesting to evaluate the effectiveness of seeding by combining the spheroids and the fibrin gel

Potential roles of extracellular vesicles in brain cell-to-cell communication

Potential roles of extracellular vesicles in brain cell-to-cell communication Extracellular vesicles (EVs) are released into thè extracellular space from both cancer and normal brain cells, and are probably able to modify thè phenotypic properties of receiving cells1. EVs released from astrocytes and neurons contain FGF2 and VEGF2'3 and induce a 'blood-brain barrier' (BBB) phenotype in cultured brain capillary endothelial cells (BCECs, unpublished results), On thè other hand, EVs from G26/24 oligodendroglioma induce apoptosis in neurons and astrocytes4-5. These effects are probably due to Fas Ligand and TRAIL, present in G26/24 vesicles4-5. Moreover, G26/24 EVs contain extracellular matrix remodeling proteases (such as ADAMTS)6, H1.0 histone protein, and H1.0 mRNA7. In particular, we previously hypothesized that G26/24 cells, and tumor cells in generai, can escape differentiation cues, and continue to proliferate by eliminating proteins, such as thè H1° linker histone (and its mRNA)7, which could otherwise block proliferation. To study vesicle release in a System that can better resemble in vivo conditions, astrocytes and BCECs were cultured on poly-L-lactic acid (PLLA) scaffolds and tested for their ability to grow and survive on this three-dimensional structures. We analyzed in parallel thè celi growth in 2D and 3D culture systems and observed thè differences in celi morphology by fluorescence analysis: threedimensional scaffolds have thè ability to guide celi growth, provide support, encourage celi adhesion and proliferation. Astrocytes8 and BCECs (unpublished results) adapted well to these porous matrices, not only remaining on thè surface, but also penetrating inside thè scaffolds. EVs released by astrocytes in these scaffolds are probably exosomes, as suggested by transmission electron microscopy pictures, and by thè presence of intracellular structures resembling multivesicular bodies. This 3D celi culture System could be further enriched to host different brain celi types, in order to set, for example, an in vitro model of BBB, that may be useful for drug delivery studies, and for thè formulation of new therapeutic strategies for thè treatment of neurological diseases. References [1] Schiera, G., Di Liegro, C.M., Di Liegro I. Int J Mol Sci. 2017, 18(12). pii: E2774. [2] Schiera, G., Proia, P., Alberti, C., Mineo, M., Savettieri, G., Di Liegro, I., 2007. J Celi Mol Med. 2007, 111(6), 1384-94. [3] Proia, P., Schiera, G., Mineo, M., Ingrassia, A.M. Santoro, G., Savettieri, G., Di Liegro, I. Int J Mol Med. 2008, 21(1), 63-7. [4] D'Agostino, S., Salamene, M., Di Liegro, I., Vittorelli, ML, Int J Oncol. 2006, 29(5), 1075-85. [5] Lo Cicero, A., Schiera, G., Proia, P., Saladino, P., Savettieri, G., Di Liegro, C.M., Di Liegro, I. Int J Oncol. 2011,39(6): 1353-7. [6] Lo Cicero, A., Majkowska, I., Nagase, H., Di Liegro, I., Troeberg, L., Matrix Biol. 2012, 31(4), 229-33. [7] Schiera, G., Di Liegro, C.M., Saladino, P., Pitti, R., Savettieri, G., Proia, P., Di Liegro, I. Int J Oncol. 2013, 43(6), 1771-6. [8] Carfì Pavia, F., Di Bella, M.A., Brucato, V., Blanda, V., Zummo, F., Vitrano, I., Di Liegro, C.M., Ghersi, G., Di Liegro, I., Schiera, G. Mol Med Rep. 2019 [Epub ahead of print]. [9] Di Bella MA, Zummo F., Carfì Pavia F., Brucato V., Di Liegro I., Schiera G. 2017, In: Microscopy and Imaging Science: practical approaches to applied research and education, pp 260-264. Ed: A. Méndez-Vilas Publisher, Formatex Research Center (Spain), ISBN-13, 978-84-942134-9-6

Medical vulnerability of individuals with Down syndrome to severe COVID-19–data from the Trisomy 21 Research Society and the UK ISARIC4C survey

Background: Health conditions, immune dysfunction, and premature aging associated with trisomy 21 (Down syndrome, DS) may impact the clinical course of COVID-19. / Methods: The T21RS COVID-19 Initiative launched an international survey for clinicians or caregivers on patients with COVID-19 and DS. Data collected between April and October 2020 (N=1046) were analysed and compared with the UK ISARIC4C survey of hospitalized COVID-19 patients with and without DS. / Findings: The mean age of COVID-19 patients with DS in the T21RS survey was 29 years (SD = 18). Similar to the general population, the most frequent signs and symptoms of COVID-19 were fever, cough, and shortness of breath. Joint/muscle pain and vomiting or nausea were less frequent (p < 0.01), whereas altered consciousness/confusion were more frequent (p < 0.01). Risk factors for hospitalization and mortality were similar to the general population with the addition of congenital heart defects as a risk factor for hospitalization. Mortality rates showed a rapid increase from age 40 and were higher in patients with DS (T21RS DS versus non-DS patients: risk ratio (RR) = 3.5 (95%-CI=2.6;4.4), ISARIC4C DS versus non-DS patients: RR = 2.9 (95%-CI=2.1;3.8)) even after adjusting for known risk factors for COVID-19 mortality. / Interpretation: Leading signs/symptoms of COVID-19 and risk factors for severe disease course are similar to the general population. However, individuals with DS present significantly higher rates of medical complications and mortality, especially from age 40. / Funding: Down Syndrome Affiliates in Action, DSMIG-USA, GiGi's Playhouse, Jerome Lejeune Foundation, LuMind IDSC Foundation, The Matthew Foundation, NDSS, National Task Group on Intellectual Disabilities and Dementia Practices

Spectroscopic and Mechanistic Studies of Heterodimetallic Forms of Metallo-β-lactamase NDM-1

In an effort to characterize the roles of each metal ion in metallo-β-lactamase NDM-1, heterodimetallic analogues (CoCo-, ZnCo-, and CoCd-) of the enzyme were generated and characterized. UV–vis, 1H NMR, EPR, and EXAFS spectroscopies were used to confirm the fidelity of the metal substitutions, including the presence of a homogeneous, heterodimetallic cluster, with a single-atom bridge. This marks the first preparation of a metallo-β-lactamase selectively substituted with a paramagnetic metal ion, Co(II), either in the Zn1 (CoCd-NDM-1) or in the Zn2 site (ZnCo-NDM-1), as well as both (CoCo-NDM-1). We then used these metal-substituted forms of the enzyme to probe the reaction mechanism, using steady-state and stopped-flow kinetics, stopped-flow fluorescence, and rapid-freeze-quench EPR. Both metal sites show significant effects on the kinetic constants, and both paramagnetic variants (CoCd- and ZnCo-NDM-1) showed significant structural changes on reaction with substrate. These changes are discussed in terms of a minimal kinetic mechanism that incorporates all of the data

SECRET domain of variola virus CrmB protein can be a member of poxviral type II chemokine-binding proteins family

<p>Abstract</p> <p>Background</p> <p>Variola virus (VARV) the causative agent of smallpox, eradicated in 1980, have wide spectrum of immunomodulatory proteins to evade host immunity. Recently additional biological activity was discovered for VARV CrmB protein, known to bind and inhibit tumour necrosis factor (TNF) through its N-terminal domain homologous to cellular TNF receptors. Besides binding TNF, this protein was also shown to bind with high affinity several chemokines which recruit B- and T-lymphocytes and dendritic cells to sites of viral entry and replication. Ability to bind chemokines was shown to be associated with unique C-terminal domain of CrmB protein. This domain named SECRET (Smallpox virus-Encoded Chemokine Receptor) is unrelated to the host proteins and lacks significant homology with other known viral chemokine-binding proteins or any other known protein.</p> <p>Findings</p> <p><it>De novo </it>modelling of VARV-CrmB SECRET domain spatial structure revealed its apparent structural homology with cowpox virus CC-chemokine binding protein (vCCI) and vaccinia virus A41 protein, despite low sequence identity between these three proteins. Potential ligand-binding surface of modelled VARV-CrmB SECRET domain was also predicted to bear prominent electronegative charge which is characteristic to known orthopoxviral chemokine-binding proteins.</p> <p>Conclusions</p> <p>Our results suggest that SECRET should be included into the family of poxviral type II chemokine-binding proteins and that it might have been evolved from the vCCI-like predecessor protein.</p