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L'espressione e la localizzazione dell'Acquaporina-4 modulano le risposte evocate dagli odoranti nell'epitelio olfattivo e l'attività neuronale basale nel bulbo olfattivo, influenzando il comportamento olfattivo
No full textL'Acquaporina-4 (AQP4) è un canale selettivo per l'acqua espresso nelle cellule gliali in tutto il sistema nervoso centrale, nonché il principale canale per l'acqua espresso nel neuropilo e coinvolto in diverse funzioni fisiologiche, che vanno dalla regolazione dell'omeostasi idrica, attraverso l'adeguamento del volume cellulare, alla modulazione dell'attività neuronale. Diverse isoforme di AQP4 sono espresse negli astrociti del bulbo olfattivo (OB) e nelle cellule simil-gliali conosciute come cellule di sostegno (SUSs) dell'epitelio olfattivo (OE). È interessante notare che i topi privi di tutte le isoforme di AQP4 mostrano un’abilità olfattiva compromessa.
Per questo motivo, il nostro obiettivo è stato investigare il ruolo fisiologico di due isoforme di AQP4: l'isoforma perivascolare AQP4ex e l'isoforma che forma l'Orthogonal Array of Particles (OAPs) (AQP4M23) nell'OE e nell'OB.
Abbiamo indagato l'impatto delle isoforme di AQP4 sull'OE, trovando una riduzione del numero di neuroni sensoriali olfattivi maturi (OSNs) nei topi privi di AQP4ex (AQP4ex-KO) o di OAPs (OAP-null). Inoltre, il numero ridotto di OSNs, SUSs e cellule basali globose (GBCs) suggerisce che le isoforme di AQP4 siano coinvolte nel mantenimento di un microambiente ottimale nell'OE, preservando la densità cellulare. Successivamente, abbiamo esplorato il ruolo di AQP4 nella modulazione delle risposte evocate dagli odoranti nell'OE attraverso l'uso dell'elettro-olfattogramma, rilevando risposte ridotte agli odoranti nei topi privi di isoforme di AQP4, insieme a una ridotta attività neuronale basale nell'OB dei topi OAP-null. Inoltre, le caratteristiche degli astrociti risultano drasticamente modificate nei due modelli KO sia durante l'attività basale che durante quella stimolata.
L'analisi delle abilità olfattive ha rivelato deficit nel cookie test nei topi AQP4ex-KO e OAP-null. Inoltre, i topi AQP4ex-KO hanno mostrato una ridotta capacità di discriminare tra diversi odoranti, mentre i topi OAP-null non sono stati in grado di riconoscerli come distinti. Anche l'apprendimento olfattivo associativo e la preferenza a diversi odoranti risultano modificati nei due modelli KO.
Nel complesso, i nostri dati evidenziano il ruolo delle isoforme di AQP4 nella modulazione dell'omeostasi neuronale, influenzando le risposte evocate dagli odoranti e la densità cellulare nell'OE. Inoltre, le isoforme di AQP4 sono coinvolte nella modulazione della morfologia degli astrociti, influenzando dunque l'attività neuronale nell'OB. Questi dati fanno luce sul ruolo delle SUSs e degli astrociti nel mediare questi processi e forniscono una base per una comprensione più approfondita della loro funzione nel controllo della funzionalità dell'OE e dell'OBAquaporin-4 (AQP4) is a water-selective channel expressed in glial cells throughout the central nervous system. It serves as the main water channel in the neuropil, and is involved in various physiological functions, ranging from regulating water homeostasis by adjusting cell volume to modulating neuronal activity. Different isoforms of AQP4 are expressed in the astrocytes of the olfactory bulb (OB) and glial-like cells known as sustentacular cells (SUSs) of the olfactory epithelium (OE). Interestingly, mice lacking all AQP4 isoforms exhibit impaired olfactory abilities. Hence, we aim to uncover the physiological role of two AQP4 isoforms, the perivascular AQP4ex isoform and the Orthogonal Array of Particle (OAP)-forming isoform (AQP4M23) in the OE and OB. Primarily, we investigated the impact of AQP4 isoforms on OE, finding reduced levels of mature olfactory sensory neurons (OSNs) in mice lacking AQP4ex (AQP4ex-KO) or OAPs (OAP-null). Moreover, the reduced number of OSNs, SUSs, and globose basal cells (GBCs) suggests that AQP4 isoforms are involved in maintaining an optimal microenvironment in the OE, preserving the overall cell density. Then, we explored the role of AQP4 in modulating odorant-evoked responses in the OE through electro-olfactogram recordings, finding reduced odorant responses in mice lacking AQP4 isoforms, along with a reduced basal neuronal activity in the OB of OAP-null. Furthermore, astrocytes’ features are drastically modified in the two KO models when under basal and stimulated activity. Olfactory ability assessments revealed deficits in odor-guided food-seeking test in AQP4ex-KO and OAP-null mice. Furthermore, AQP4ex-KO mice showed a reduced ability to discriminate between different odorants, while OAP-null mice were unable to recognize them as distinct. Moreover, associative olfactory learning and odorant preference are even modified in the two KO models. Overall, our data highlight the role of AQP4 isoforms in modulating neuronal homeostasis, affecting odorant-evoked responses and cell density in the OE. On the other hand, AQP4’ isoforms are even involved in modulating the astrocytes’ morphology by affecting the neuronal activity in the OB. These results shed light on SUSs and astrocytes involvement in mediating these processes and establish a foundation for further understanding their role in controlling OE and OB physiolog
The Aquaporin-4 Expression and Localization in the Olfactory Epithelium Modulate the Odorant-Evoked Responses and Olfactory-Driven Behavior
No full textAquaporin-4 (AQP4) is a water-selective channel expressed in glial cells throughout the central nervous system (CNS). It serves as the primary water channel in the neuropil and plays roles in physiological functions, including regulating water homeostasis by adjusting cell volume and modulating neuronal activity. Different isoforms of AQP4 are expressed in glial-like cells known as sustentacular cells (SUSs) of the olfactory epithelium (OE). Notably, mice lacking all AQP4 isoforms exhibit impaired olfactory abilities. Therefore, we aim to uncover the physiological role of AQP4 isoforms, particularly the AQP4ex isoforms (AQP4M1ex, AQP4M23ex) and the orthogonal array of particles (OAPs)-forming isoform (AQP4M23) in the OE. We investigated the impact of AQP4 isoforms on the OE, observing a reduced number of mature olfactory sensory neurons (OSNs), SUSs, and globose basal cells (GBCs) in mice lacking AQP4ex (AQP4ex-KO) or OAPs (OAP-null). This suggests that AQP4 isoforms are involved in maintaining an optimal microenvironment in the OE, preserving cell density. Next, we explored the role of AQP4 in modulating odorant-evoked responses through electro-olfactogram recordings, where we found reduced odorant responses in mice lacking AQP4 isoforms. Assessments of olfactory ability revealed deficits in odor-guided food-seeking behavior in both AQP4ex-KO and OAP-null mice. Furthermore, AQP4ex-KO mice exhibited a diminished ability to discriminate between different odorants, while OAP-null mice were unable to recognize them as distinct. Overall, our data highlight the role of AQP4 isoforms in modulating neuronal homeostasis, influencing odorant-evoked responses and cell density in the OE, with AQP4ex emerging as a key regulator despite its low abundance
High OXPHOS efficiency in RA-FUdr-differentiated SH-SY5Y cells: involvement of cAMP signalling and respiratory supercomplexes
Get PDFNeurons are highly dependent on mitochondria to meet their bioenergetic needs and understanding the metabolic changes during the differentiation process is crucial in the neurodegeneration context. Several in vitro approaches have been developed to study neuronal differentiation and bioenergetic changes. The human SH-SY5Y cell line is a widely used cellular model and several differentiation protocols have been developed to induce a neuron-like phenotype including retinoic acid (RA) treatment. In this work we obtained a homogeneous functional population of neuron-like cells by a two-step differentiation protocol in which SH-SY5Y cells were treated with RA plus the mitotic inhibitor 2-deoxy-5-fluorouridine (FUdr). RA-FUdr treatment induced a neuronal phenotype characterized by increased expression of neuronal markers and electrical properties specific to excitable cells. In addition, the RA-FUdr differentiated cells showed an enrichment of long chain and unsaturated fatty acids (FA) in the acyl chain composition of cardiolipin (CL) and the bioenergetic analysis evidences a high coupled and maximal respiration associated with high mitochondrial ATP levels. Our results suggest that the observed high oxidative phosphorylation (OXPHOS) capacity may be related to the activation of the cyclic adenosine monophosphate (cAMP) pathway and the assembly of respiratory supercomplexes (SCs), highlighting the change in mitochondrial phenotype during neuronal differentiation
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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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