1,720,957 research outputs found
Combining a tetracycline (Tet)-inducible gRNA system and CRISPRa for titratable and timely controlled enhancement of endogenous SHISA3 activation in human induced pluripotent stem cells (hiPSC)
No full textTowards increasing the possibility for temporal control of gene expression using CRISPR activation (a) systems, we generated homozygous human induced pluripotent stem cell (hiPSC) lines carrying a doxycycline (dox)-inducible guide(g)-RNA construct targeting the SHISA3 transciptional start site, as proof-of-principle, or a non targeting gRNA as a control. The dox-inducible gRNA cassette was inserted into the human ROSA26 locus in a line with dCas9VPR integrated at the AAVS1 locus (CRISPRa/Tet-iSHISA3). Pluripotency, genomic integrity and differentiation potential into all three germ layers were maintained. Dox-dependent gene induction was validated in hiPSCs as well as derived fibroblasts. These lines provide an attractive tool for cellular reprogramming in hiPSC-derived cells in a timely controlled manner
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
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
SHISA3, a novel Wnt-dependent Signature in the Developing and Failing Heart
No full textDie Mechanismen der Entwicklung vaskulärer Zellen während der Kardiogenese können genutzt werden, um neue Wege der kardialen Regeneration im erkrankten Herzen zu entdecken, mit besonderem Fokus auf dem Epikard als therapeutisches Target. Vorangegangene Studien haben gezeigt, dass die Aktivierung des Wnt/β-Catenin-Signalwegs zur Reprogrammierung von Kardiomyozyten und vaskulären Zellen führt, was im erwachsenen Herzen ein progredientes pathologisches Umbauprogramm zur Folge hat. In dieser Studie wurde eine bislang unbekannte Population von SHISA3-exprimierenden Zellen mit kardiovaskulärem Progenitor-Potential untersucht, die eine Re-Expression von SHISA3 im erkrankten Herzen aufwiesen. In Maus-Embryonen wurden SHISA3-positive Zellen, die frühe vaskuläre Markergene exprimieren, zum Zeitpunkt E 14.5 vorwiegend im Subepikard gefunden. Ziel meiner Arbeit war es, die Rolle von SHISA3 im Differenzierungsweg humaner mesenchymaler Zellen zu untersuchen, die aus subepikardialen kardiovaskulären Vorläuferzellen stammen.
In Übereinstimmung mit zuvor beschriebenen in vivo-Ergebnissen zeigte sich in humanen induzierten pluripotenten Stammzellen (hiPSCs), die zu epikardialen Zellen (EPI-Zellen) und deren Abkömmlingen, den glatten Gefäßmuskelzellen (vSMCs) und Fibroblasten, differenziert wurden, eine frühe Hochregulation von SHISA3, verbunden mit einem darauffolgenden kontinuierlichen Rückgang an SHISA3-Expression. Um die SHISA3-positive Population als gemeinsamen Pool früher vaskulärer Vorläuferzellen weiter zu analysieren, wurde eine Single-Cell RNA-Sequenzierung dieser Zellen am Tag 8 der Differenzierung durchgeführt. Diese Analyse identifizierte SHISA3 als Marker-Gen, das ausschließlich in frühen Übergangszellen exprimiert wird, die sich im Prozess eines epikardial-mesenchymalen Identitätswechsels befinden.
Um die Auswirkungen einer SHISA3-Überexpression in diesen Modellen präzise untersuchen zu können, wurden transgene hiPSC-Linien generiert und charakterisiert. Mithilfe der CRISPRa-Technologie in Kombination mit einer Doxyzyklin-induzierbaren guide RNA war in diesen Linien eine kontrollierte endogene Aktivierung von SHISA3 möglich, während eine nicht-zielgerichtete guide RNA als Kontrolle diente. Ausgehend von einer epikardialen Population wurden mittels Doxycyclin SHISA3-aktivierte Zellen zu vSMCs differenziert, gefolgt von einer RNA-Gesamttranskriptomanalyse. Dabei zeigten sich signifikante Effekte auf die Regulation der TGFβ- sowie der p53-Signalwege.
Da diese Signalwege eine zentrale Rolle in der epithelial-mesenchymalen Transition (EMT) spielen, charakterisiert dies SHISA3 als potenziellen Schlüsselregulator der vaskulären Zellentwicklung aus dem Epikard. Darüber hinaus wurden Hinweise auf einen wechselseitigen Kontrollmechanismus zwischen SHISA3 und TGFβ in EPI-Zellen gefunden, die mit TGFβ-Inhibitoren behandelt wurden: Dies führte zu einer anhaltenden Expression von SHISA3 während der Entwicklung.
Diese Ergebnisse charakterisieren SHISA3 als exklusiven Marker unreifer, vom Epikard abgeleiteter Vorläuferzellen, der die Festlegung des kardiovaskulären Differenzierungswegs in der Entwicklung und möglicherweise auch bei kompensatorischer fetaler Reprogrammierung im erkrankten Herzen beeinflusst. Die erhöhte Expression von SHISA3 während der frühen Entwicklung von vSMCs aus der beschriebenen SHISA3-Genaktivator-hiPSC-Linie deutet auf eine SHISA3-abhängige Regulation kritischer, an der EMT beteiligter Signalwege hin. Dies unterstreicht die bedeutende Rolle von SHISA3 bei der mesenchymalen Identätsfindung während der durch das Epikard vermittelten, EMT-getriebenen Entwicklung vaskulärer Zellen.Understanding how vascular cells develop can be used to discover new paths of cell renewal
within the diseased heart, with a particular focus on the epicardium for cardiac regeneration.
Previous studies have shown that activating the Wnt/β-catenin pathway leads to the
reprogramming of cardiomyocytes and vascular cells, resulting in harmful changes in the
adult heart. In this study, a previously unknown population of SHISA3-expressing cells,
distinct from cardiomyocytes, was discovered in both developing and diseased hearts. I
aimed to investigate the role of these cells in determining the fate of human vascular cells
derived from sub-epicardial cardiovascular progenitors using human induced pluripotent
stem cell (hiPSC) derived in vitro models.
In mouse embryos at day 14.5, SHISA3+ cells expressing alpha smooth muscle actin were
predominantly found in the sub-epicardium, aligning with the presence of immature vascular
markers. Consistent with previously described in vivo findings, early upregulation of SHISA3
along with a gradual decline was displayed in hiPSCs differentiated towards epicardial cells
(EPI cells) and their vascular smooth muscle cell (vSMC) and fibroblast derivatives. To
further confirm the SHISA3+ population as a shared pool of early vascular progenitors,
whole cell single cell sequencing of these cells was conducted at differentiation day 8. This
analysis unveiled SHISA3 as a marker gene exclusively expressed in early transitional cells,
undergoing an epicardial-to-mesenchymal shift in cell identity. To understand the impact of
SHISA3 overexpression on these models in a precisely controlled manner, I created and
analyzed transgenic hiPSC lines. Using the CRISPRa technology coupled with a doxycycline
inducible guide RNA, these lines allowed for inducible endogenous SHISA3 activation,
whereas a non-targeting guide RNA served as control. Originating from an epicardial state,
SHISA3-acitvated cells were directed towards vSMCs with subsequent whole transcriptome
RNA analysis. Here, notable effects on the regulation of TGFβ as well as p53 signaling
pathways were revealed. Given that these pathways play fundamental roles in the epithelial-to-
mesenchymal transition (EMT) process, this characterizes SHISA3 as a potential key
regulator of vascular cell development from the epicardium. Furthermore, evidence for a
SHISA3- and TGFβ-mediated mutual control mechanism was found in EPI cells treated
with TGFβ-inhibitors, leading to sustained expression of SHISA3 throughout development.
These findings characterized SHISA3 as an exclusive marker of early epicardium-derived
transitional progenitor cells, influencing cardiovascular cell fate determination in
development and, potentially, compensatory fetal reprogramming in the diseased heart.
Increased expression of SHISA3 during the early development of vSMCs from the described
innovative SHISA3 gene activator hiPSC line indicated a SHISA3-dependent regulation of
critical pathways involved in EMT. This underscores a significant role for SHISA3 in
determining cell fate during epicardial EMT-driven vascular cell development.2026-09-1
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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