1,721,018 research outputs found
COMBINING TRANSLATION READTHROUGH INDUCING DRUGS AND NONSENSE MEDIATED DECAY PATWHAY INHIBITION TO THE CFTR RESCUE IN CYSTIC FIBROSIS CELL MODEL SYSTEM
Full text linkNonsense mutations affect 10% of patients with cystic
fibrosis and produce a premature termination codon in CFTR
(Cystic Fibrosis Transmembrane Conductance Regulator)
mRNA causing early termination of translation and leading to
lack of CFTR function. A potential therapy for nonsense mutations provides the use of small molecules able to overcome the
premature stop codon (PTC) by a readthrough mechanism that
lead to synthesis a complete CFTR protein. Despite the good
results obtained from this approach, TRIDs efficiency is considerably reduced by the poor amount of target transcript, that is
the mRNA containing the PTC. The readthrough, indeed, does
not occur on the totality of target transcripts because of their
degradation due to the nonsense mediated decay pathway
(NMD). This pathway provides the degradation of mRNA harboring premature stop codon to prevent the production of
altered polypeptides. In contrast, the activity of this pathway
interferes with the effectiveness of the readthrough drugs, limiting the mRNA concentration of the target protein. Thus, a
promising strategy for nonsense mutation treatment is a combined use of readthrough agents and factors that attenuate the
nonsense mRNA decay. By silencing the UPF1 mRNA/protein, the activity of the NMD pathway was reduced, in FRT
cells CFTR W1282X. Alternatively, caffeine was used as specific
inhibitor of the UPF1 activity, to increase the efficiency of
readthrough molecules (NV848 and NV914) in FRT cells
CFTRW1282X cells. In both cases, the combined treatment:
NV848 or NV914/caffeine and NV848 or
NV914/UPF1siRNA caused an increase of CFTRW1282X
mRNA level followed by the rescue of the CFTR expression
and functionality. However, unexpectedly, despite the higher
CFTRW1282X mRNA level in caffeine treated samples, both
expression and functionality CFTR rescue resulted slightly
lower than the recovery achieved by UPF1 silencing. Our
results indicate that modulation of NMD pathway, although
still to be optimized, could be a promising approach in order
to increase TRIDs effects in presence of stop mutations
TRPM8 channel activation reduces the spontaneous contractions in human distal colon
Full text linkThe transient receptor potential-melastatin 8 (TRPM8) is a non-selective Ca2+-permeable
channel, activated by cold, membrane depolarization, and different cooling compounds.
TRPM8 expression has been found in gut mucosal, submucosal, and muscular nerve endings.
Although TRPM8 plays a role in pathological conditions, being involved in visceral pain and
inflammation, the physiological functions in the digestive system remain unclear as yet. The aims of
the present study were: (i) to verify the TRPM8 expression in human distal colon; (ii) to examine
the effects of TRPM8 activation on colonic contractility; (iii) to characterize the mechanism of
action. Reverse transcriptase-polymerase chain reaction (RT-PCR) and western blotting were used
to analyze TRPM8 expression. The responses of human colon circular strips to different TRPM8
agonists [1-[Dialkyl-phosphinoyl]-alkane (DAPA) 2–5, 1-[Diisopropyl-phosphinoyl]-alkane (DIPA)
1–7, DIPA 1–8, DIPA 1–9, DIPA 1–10, and DIPA 1–12) were recorded using a vertical organ bath.
The biomolecular analysis revealed gene and protein expression of TRPM8 in both mucosal and
smooth muscle layers. All the agonists tested, except-DIPA 1–12, produced a concentration-dependent
decrease in spontaneous contraction amplitude. The effect was significantly antagonized by
5-benzyloxytryptamine, a TRPM8 antagonist. The DIPA 1–8 agonist resulted in the most efficacious
and potent activation among the tested molecules. The DIPA 1–8 effects were not affected by
tetrodotoxin, a neural blocker, but they were significantly reduced by tetraethylammonium chloride,
a non-selective blocker of K+ channels. Moreover, iberiotoxin, a blocker of the large-conductance
Ca2+-dependent K+-channels, but not apamin, a blocker of small-conductance Ca2+-dependent K+
channels, significantly reduced the inhibitory DIPA 1–8 actions. The results of the present study
demonstrated that TRPM8 receptors are also expressed in human distal colon in healthy conditions
and that ligand-dependent TRPM8 activation is able to reduce the colonic spontaneous motility,
probably by the opening of the large-conductance Ca2+-dependent K+-channels
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
OXADIAZOLE DERIVATIVES FOR THE TREATMENT OF GENETIC DISEASES DUE TO NONSENSE MUTATIONS
No full textAre disclosed oxadiazole derivatives, their use as medicaments and in particular for the treatment of diseases associated with the presence of a nonsense mutation in the gene or a premature stop codon in the mRNA, pharmaceutical formulation comprising said oxadiazole derivatives and prodrug or mixture thereof and the methods for the preparation of said Oxadiazole derivatives
PERSONALIZED MEDICINE FIGHTING NONSENSE DISEASES: EXPLORATION OF NV MOLECULES MECHANISM OF ACTION IN PURE-LITE SYSTEM AND THEIR READTHROUGH ACTIVITY IN CHOROIDEREMIA NONSENSE MODEL
No full textPrecision medicine represents a new approach in genetic medicine for treating a patient's mutation profile. Nonsense mutations cause 11% of inherited genetic diseases, including Choroideremia (CHM), Cystic fibrosis (CF), Duchenne Muscular Dystrophy (DMD), and some Cancers. Choroideremia is an X-linked disease associated with many retinal disorders. This retinal dystrophy causes the progressive degeneration of the choriocapillaris, photoreceptors, and retinal pigment epithelium. The CHM gene codifies for a 95 kDa, known as rab escort protein 1 (Rep1), involved in the intracellular trafficking and prenylation of polypeptides, a post-translational modification fundamental for the correct functionality of specific proteins. Nonsense mutations represent about 34% of mutations in the CHM gene. These mutations prematurely introduce a premature termination codon (PTC: TGA, TAG, and TAA) in the mRNA frame, causing a truncated and non-functional protein that will be eliminated from intracellular surveillance pathways. Nowadays there is no cure for diseases caused by nonsense mutations, but in the last decades, promising results have come from a pharmacological approach, called suppression therapy. This approach uses specific drugs having readthrough activity, known as TRIDs (Translational Readthrough Inducing Drugs), which permit the insertion of a near-cognate-tRNA in correspondence with a PTC during protein translation, allowing the correct development of a functional full-length protein. Our study is focused on investigating three molecules, NV848, NV914 and NV930, patented by Pibiri-Lentini group, that have shown readthrough activity in different nonsense model diseases. Specifically, elucidating their Mechanism of Action in the PURE-LITE system and exploring their readthrough activity in a choroideremia nonsense model system have been the goals of our efforts. PURE-LITE system is a highly purified, eukaryotic cell-free protein synthesis system, that allows the investigation of both the termination of protein synthesis in the P-site catalyzed by the RF complex (eRF1/eRF3/ribosome) and the readthrough via mispairing at the termination codon by a near-cognate tRNA when a PTC enter into the 40S A-site ribosome subunit. Simultaneously, chronic treatment and protein expression analyses was performed on Choroideremia nonsense cell model system to study their readthrough activity. Our results have shown both that the mechanism of action of these molecules is different by their precursor Ataluren, and in addition their readthrough activity with the rescue of Rep1 protein
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Production of CHM R293X cell model system to study the rescue of the Rab Escort Protein-1 expression by TRIDs nonsense suppression activity
No full textChoroideremia is an inherited genetic disorder caused by several mutations in the CHM gene, which codifies for Rep1 protein strictly linked in intravesicular trafficking. The Rep1 lack causes choroid and photoreceptors degeneration, leading firstly to night blindness and at last to complete blindness. About 39% of mutations on the CHM gene are represented by nonsense mutations, which insert a premature termination codon in the reading frame of respective mRNA, with the production of truncated non-functional protein. Nowadays there is no cure for diseases caused by nonsense mutations, but a promising approach is the suppression therapy using TRIDs molecules (translational readthrough-inducing drugs). In our study, a CHMR293X/R293X cell model system was produced to evaluate the activity of three new optimized molecules (NV848, NV914, and NV930) in the rescue of the Rab-Escort-Protein-1 (Rep1) expression
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