1,721,089 research outputs found
Mesenchymal and Induced Pluripotent Stem Cells-Derived Extracellular Vesicles: The New Frontier for Regenerative Medicine?
Full text linkRegenerative medicine aims to repair damaged, tissues or organs for the treatment of various diseases, which have been poorly managed with conventional drugs and medical procedures. To date, multimodal regenerative methods include transplant of healthy organs, tissues, or cells, body stimulation to activate a self-healing response in damaged tissues, as well as the combined use of cells and bio-degradable scaffold to obtain functional tissues. Certainly, stem cells are promising tools in regenerative medicine due to their ability to induce de novo tissue formation and/or promote organ repair and regeneration. Currently, several studies have shown that the beneficial stem cell effects, especially for mesenchymal stem cells (MSCs) and induced pluripotent stem cells (iPSCs) in damaged tissue restore are not dependent on their engraftment and differentiation on the injury site, but rather to their paracrine activity. It is now well known that paracrine action of stem cells is due to their ability to release extracellular vesicles (EVs). EVs play a fundamental role in cell-to-cell communication and are directly involved in tissue regeneration. In the present review, we tried to summarize the molecular mechanisms through which MSCs and iPSCs-derived EVs carry out their therapeutic action and their possible application for the treatment of several diseases
Naphthalimide Imidazolium-Based Supramolecular Hydrogels as Bioimaging and Theranostic Soft Materials
No full text1,8-Naphthalimide-based imidazolium salts differing for the alkyl chain length and the nature of the anion were synthesized and characterized to obtain fluorescent probes for bioimaging applications. First, their self-assembly behavior and gelling ability were investigated in water and water/dimethyl sulfoxide binary mixtures. Only salts having longer alkyl chains were able to give supramolecular hydrogels, whose properties were investigated by using a combined approach of fluorescence, resonance light scattering, and rheology measurements. Morphological information was obtained by scanning electron microscopy. In addition, conductive properties of organic salts in solution and gel state were analyzed. Imidazolium salts were successfully tested for their possible application as bioimaging and cytotoxic agents toward three cancer cell lines and a nontumoral epithelial cell line. Characterization of their behavior was performed by MTT and cell-based assays. Finally, the biological activity of hydrogels was also investigated. Collectively, our findings showed that naphthalimide-based imidazolium salts are promising theranostic agents and they were able to preserve their biological properties also in the gel phase
Chiral and fluorescent supramolecular gels: study of properties and insights into applications
Full text linkIdrogel fluorescenti per applicazioni biomediche
No full textLo studio di idrogel supramolecolari da utilizzare in ambito biomedico è
in continua espansione. Questo è dovuto al fatto che, così come gli idrogel polimerici,
mostrano eccellenti proprietà meccaniche, ma possono anche essere
sottoposti reversibilmente a rigonfiamento o a transizioni gel-sol in risposta a
stimoli esterni (temperatura, pH, enzimi, agenti redox).1Ad esempio, la buona
risposta degli idrogel supramolecolari agli stimoli fisiologici, insieme alla
loro elevata biodegradabilità e biocompatibilità, ne ha permesso l’utilizzo per
la diagnosi tumorale. Solitamente, questi materiali sono facilmente assimilati
dalle cellule e hanno la funzione di carrier per le molecole attive nel bioimaging.
1Alla luce di queste premesse e della spiccata attività antimicrobica
precedentemente riscontrata su idrogel formati da sali di imidazolio,2 si è pensato
di sintetizzare nuovi sali organici di imidazolio fluorescenti, che potessero
assolvere alla duplice funzione di gelator e di agente per il bioimaging.
Sono stati ottenuti idrogel fluorescenti che hanno mostrato interessanti
proprietà chimico-fisiche (temperatura di transizione gel-sol, risposta a
stimoli esterni, reologia, morfologia, indagini spettrofluorimetriche) e biologiche
(attività antiproliferativa, bioimaging su cellule tumorali in vitro e
rilascio controllato del gelator in soluzione fisiologica)
Investigating CRISPR-CAS13b as a tool for the RNA editing of CFTR mRNA with premature stop codon
Full text linkBackground and Rationale
Some CF patients are compound heterozygous or homozygous for
nonsense mutations in the CFTR gene. Mutant CFTR gene coding for
transcripts with premature termination codons (PTCs) is responsible
for truncated CFTR protein and for a severe form of the disease. In a
precision medicine framework the “REPAIRv2” (RNA Editing for
Programmable A to I Replacement v2) tool, developed in the laboratory
of Dr. Feng Zhang (USA), seems a good alternative to restore
the full-length CFTR protein by editing its mRNA containing PTCs.
This new approach is based on the possibility of targeting a deaminase
enzyme (huADAR2) to a specific Adenosine, to be edited to Inosine
(G analogue), on the mutant RNA by a specific guide RNA
(gRNA), complementary to the target regions, and a Cas protein.
Hypothesis and objectives
We applied the new CRISPR/dCas13b based molecular tool of RNA
editing (REPAIRv2) to correct the premature stop codon UGA, changing
to UGG, in the H2bGFPopal and CFTRW1282X mRNAs with the
purpose of recovering the full-length proteins.Essential Methods
We designed and cloned the gRNAs needed to target the REPAIRv2
system to the Adenine to be modified. By site-directed mutagenesis
we introduced a premature stop codon, W1282X, in the CFTR cDNA.
Human HeLa cells expressing the H2BGFPopal mRNA, FRT cells expressing
CFTRW1282X and IB3.1 airway epithelial human cells
(CFTRΔ508/W12382X) were co-transfected with the plasmids coding
for the recombinant protein dCAS13b/ADAR2DD, and for the gRNAs.
Fluorescence microscopy was used to analyse the editing results.
Results
Direct fluorescence microscopy and immunofluorescence analyses
detecting the corrected proteins (H2BGFP and CFTR, respectively)
suggest that the REPAIRv2 system was able, in different cell lines, to
edit the H2BGFPopal and the CFTRW1282X mRNA. However, the rate
of editing does not seem high. Indeed, when RNA was purified from
transfected cell, retro-transcribed and amplified base correction was
not detectable by standard DNA sequencing and western blot.
Conclusions
Collectively, our results indicate that the REPAIRv2 tool is able to edit
the UGA premature stop codon present in the HeLa-H2BGFPopal
cells and in engineered FRTW1282X cells harbouring the UGA PTC in
the CFTR mRNA. Furthermore, the REPAIRv2 tool worked in the IB3.1
cells suggesting its ability to edit endogenous UGA premature stop
codon. Anyway, enhance the delivery of the plasmids as well increase/
stabilize the target mRNA to be edited, seem necessary to improve
the efficiency of REPAIRv2.
References
1. Cox DBT, Gootenberg JS, Abudayyeh OO, Franklin B, Kellner MJ, Joung J,
Zhang F.- RNA editing with CRISPR-Cas13. Science. 2017 Nov 24; 358
(6366):1019-1027)
2. Lentini L, Melfi R, Di Leonardo A, Spinello A, Barone G, Pace A, Palumbo
Piccionello A, Pibiri I. Toward a rationale for the PTC124 (Ataluren)
promoted readthrough of premature stop codons: a computational
approach and GFP-reporter cell-based assay. Mol Pharm. 2014 Mar
3;11(3):653-64.
Acknowledgment FFC#5/2018 funded by FFC and supported by Delegazione
FFC di Palerm
Toxic effects induced by vanadium on sea urchin embryos
No full textVanadium, a naturally occurring element widely distributed in soil, water and air, has received considerable interest because its compounds are often used in different applications, from industry to medicine. While the possible medical use of vanadium compounds is promising, its potential harmful effects on living organisms are still unclear. Here, for the first time, we provide a toxicological profile induced by vanadium on Paracentrotus lividus sea urchin embryos, reporting an integrated and comparative analysis of the detected effects reflecting vanadium-toxicity. At the morphological level we found a dose-dependent induction of altered phenotypes and of skeletal malformations. At the molecular levels, vanadium-exposed embryos showed the activation of the cellular stress response, in particular, autophagy and a high degree of cell-selective apoptosis in a dose-dependent manner. The stress response mediated by heat shock proteins seems to counteract the damage induced by low and intermediate concentrations of vanadium while the high cytotoxic concentrations induce more marked cell death mechanisms. Our findings, reporting different mechanisms of toxicity induced by vanadium, contribute to increase the knowledge on the possible threat of vanadium for marine organisms and for both environmental and human health
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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