1,720,956 research outputs found
Design of new molecules as a therapeutic strategy for Cystic Fibrosis
No full textThe approval of Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) modulator therapy by global health agencies over the past few decades has fundamentally changed the course of patients affected by Cystic Fibrosis (CF). CFTR is a membrane protein that functions as a chloride channel in epithelial cells. Mutations in the CFTR gene lead to absent or impaired chloride transport across the apical membranes, primarily in the respiratory and glandular epithelia. This defect results in the extracellular accumulation of thick, sticky mucus, leading to chronic conditions such as sinusitis, bronchitis, pneumonia, and asthma, often refractory to standard therapy, as well as nasal polyposis, digital clubbing, and bronchiectasis.
CFTR modulators are categorized, based on their mechanism of action, as correctors, which enhance CFTR folding and trafficking to the cell surface, and potentiators, which improve ion transport through CFTR channels already present on the apical membrane. The four currently approved modulators are the potentiator Ivacaftor (VX770 or IVA) and the correctors Lumacaftor (VX809 or LUM), Tezacaftor (VX661 or TEX), and Elexacaftor (VX445 or ELX). Combinations of these modulators, such as the triple combination Ivacaftor/Tezacaftor/Elexacaftor (Kaftrio®), represent the best therapeutic option available for patients with sensitive CFTR mutations, including the most common one, the phenylalanine 508 deletion (F508del-CFTR). However, current therapies do not guarantee complete CFTR functional recovery, highlighting the need for developing new molecules to fill these therapeutic gaps.
This thesis reports on the development and study of novel molecules featuring an arylthiazole scaffold for their potential to restore CFTR functionality. The goal was to develop compounds that are more active than those already clinically approved, both when administered alone and in combination, aiming for a synergistic effect due to complementary mechanisms of action between them and already approved modulators.
Functional channel activity assays using the Yellow Fluorescent Protein (YFP) reporter in Fisher Rat Thyroid (FRT) and CFBE41o- cells stably expressing F508del-CFTR demonstrated a significant additive/synergistic effect when the novel VX809-hybrids 2a and 3a were combined with VX445.
Furthermore, eight other newly synthesized compounds (4a, 5a, 1b, 2b, 3b, 7b, and 1c), when tested individually, significantly increased F508del-CFTR activity compared to the vehicle treatment in CFBE bronchial epithelial cells. Notably, the combinations 2b + 5a and 7b + 4a resulted in
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approximately 20% and 29% greater F508del-CFTR rescue, respectively, than the clinically used VX809 + VX445 combination.
To confirm this efficacy, a functional measurement of CFTR activity using the Fluorescence Microplate Polarimetry (FMP) assay was performed in Human Nasal Epithelial (HNE) primary cells from four CF patients homozygous for the F508del-CFTR mutation. The results confirmed that the novel corrector combinations (2b + 5a and 7b + 4a) significantly increased FSK-activated and VX770-potentiated F508del-CFTR function compared to the rescue levels mediated by either the VX809 + VX445 or VX661 + VX445 combinations in HNE cells.
Finally, recognizing the emerging role of molecular chaperone modulators as a strategy to enhance F508del-CFTR rescue, combining them with already approved modulators, a small library of Hsc70/Hsp70 modulators was developed based on the scaffold of MKT-077, a known allosteric Hsp70 inhibitor. Among the new library, three MKT-077 analogues, i.e. DL79, DL90, and AP161, showed an inhibitory effect on human recombinant Hsp70 ATPase activity. Significantly, DL79 demonstrated a higher ability than MKT-077 to enhance the corrective effect of VX809 on F508del-CFTR in CFBE41o- cells at a remarkably low concentration. The combination of DL79 with other clinically approved correctors revealed a significant synergistic interaction with VX661 and with the VX661/VX445 combination, though no meaningful effect was observed in combination with VX445 alone.
Results reported in this thesis identified and characterized novel CFTR modulators and molecular chaperone enhancers that demonstrate superior efficacy, particularly in combination, compared to current standard-of-care therapies for F508del-CFTR.
In summary, these results provide strong preclinical evidence supporting the further development of these novel arylthiazole correctors and the Hsp70 modulators as potential next-generation therapeutic agents for CF patients with the F508del-CFTR mutation
LEAD OPTIMIZATION OF MKT-077 ANALOGUES AS HSP70 ALLOSTERIC INHIBITORS COMBINED WITH F508DEL CFTR CORRECTORS: A MULTI DRUG APPROACH TO CONTRAST CYSTIC FIBROSIS
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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
Structure-guided combination of novel CFTR correctors to improve the function of F508del-CFTR in airway epithelial cells
No full textAlthough remarkable rescue has been achieved for treatment of Cystic Fibrosis (CF) by the combination of two correctors (VX-661, VX-445) and one potentiator (VX-770), the stability and trafficking defects induced by the most common mutation, F508del, are not completely reversed. Therefore, more effective CFTR correctors are still needed. We employed in silico and molecular modelling approaches to design and probe the binding site of novel series of CFTR correctors (a-c). Structure-based studies allowed us to design and synthesize novel class I (b series) and class II (a series) modulators. Thus, class I modulator activity relies on interactions with Met152, Phe81, Phe191, Trp361. The design of class II corrector could be managed via NBD2-ligand H-bonds, involving Gln1291 or Val1288. Furthermore, c compounds were proposed featuring putative dual corrector ability (2c) and class II corrector behavior (1c). Functional measurements in F508del-CFTR CFBE cells and primary nasal epithelial cells demonstrated that eight of fourteen compounds acted as CFTR correctors and the F508del-CFTR rescue was comparable to the level measured after VX-809 or VX-445 treatment in CFBE cells. Through rational selection based on molecular docking studies and mechanisms of action, we showed that combination of compounds (7a+1b and 2a+2b) targeting distinct domains of CFTR, can additively/synergistically rescue F508del-CFTR function in both CFBE cell line and primary nasal cells. Our study demonstrated that in silico and in vitro approaches to develop and investigate the mechanism of action of novel CFTR correctors could be a tool to optimize the combination correctors therapy to synergistically rescue mutated CFTR
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
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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