207 research outputs found
An expandable walking in place platform
The control of locomotion in 3D virtual environments should be an ordinary task, from the user point-of-view. Several navigation metaphors have been explored to control locomotion naturally, such as: real walking, the use of simulators, and walking in place. These have proven that the more natural the approach used to control locomotion, the more immerse the user will feel inside the virtual environment. Overcoming the high cost and complexity for the use of most approaches in the field, we introduce a walking in place platform that is able to identify orientation, speed for displacement, as well as lateral steps, of a person mimicking walking pattern. The detection of this information is made without use of additional sensors attached to user body. Our device is simple to mount, inexpensive and allows almost natural use, with lazy steps, thus releasing the hands for other uses. Also, we explore and test a passive, tactile surface for safe use of our platform. The platform was conceived to be utilized as an interface to control navigation in virtual environments, and augmented reality. Extending our device and techniques, we have elaborated a redirection walking metaphor, to be used together with a cave automatic virtual environment. Another metaphor allowed the use of our technique for navigating in point clouds for tagging of data. We tested the use of our technique associated with two different navigation modes: human walking and vehicle driving. In the human walking approach, the virtual orientation inhibits the displacement when sharp turns are made by the user. In vehicle mode, the virtual orientation and displacement occur together, more similar to a vehicle driving approach. We applied tests to detect preferences of navigation mode and ability to use our device to 52 subjects. We identified a preference for the vehicle driving mode of navigation. The use of statistics revealed that users learned easily the use of our technique for navigation. Users were faster walking in vehicle mode; but human mode allowed precise walking in the virtual test environment. The tactile platform proved to allow safe use of our device, being an effective and simple solution for the field. More than 200 people tested our device: UFRGS Portas Abertas in 2013 and 2014, which was a event to present to local community academic works; during 3DUI 2014, where our work was utilized together with a tool for point cloud manipulation. The main contributions of our work are a new approach for detection of walking in place, which allows simple use, with naturalness of movements, expandable for utilization in large areas (such as public spaces), and that efficiently supply orientation and speed to use in virtual environments or augmented reality, with inexpensive hardware.O controle da locomoção em ambientes virtuais 3D deveria ser uma tarefa simples, do ponto de vista do usuário. Durante os anos, metáforas para navegação têm sido exploradas para permitir o controle da locomoção naturalmente, tais como: caminhada real; uso de simuladores e imitação de caminhada. Estas técnicas provaram que, quanto mais natural à abordagem utilizada para controlar a locomoção, mais imerso o usuário vai se sentir dentro do ambiente virtual. Superando o alto custo e complexidade de uso da maioria das abordagens na área, introduzimos uma plataforma para caminhada no lugar, (usualmente reportado como wal king in place), que é capaz de identificar orientação, velocidade de deslocamento, bem como passos laterais, de uma pessoa imitando a caminhada. A detecção desta informação é feita sem o uso de sensores presos no corpo dos usuários, apenas utilizando a plataforma. Nosso dispositivo é simples de montar, barato e permite seu uso por pessoas comuns de forma quase natural, com passos pequenos, assim deixando as mãos livres para outras tarefas. Nós também exploramos e testamos uma superfície táctil passiva para utilização segura de nossa plataforma. A plataforma foi concebida para ser utilizada como uma interface para navegação em ambientes virtuais. Estendendo o uso de nossa técnica e dis positivo, nós elaboramos uma metáfora para caminhada redirecionada, para ser utilizada em conjunto com cavernas de projeção, (usualmente reportado como Cave automatic vir tual environment (CAVE)). Criamos também uma segunda metáfora para navegação, a qual permitiu o uso de nossa técnica para navegação em nuvem de pontos, auxiliando no processo de etiquetagem destes, como parte da competição para o 3D User Interface que ocorreu em Minessota, nos Estados Unidos, em 2014. Nós testamos o uso da técnica e dispositivos associada com duas nuances de navegação: caminhada humana e controle de veiculo. Na abordagem caminhada humana, a taxa de mudança da orientação gerada pelo usuário ao utilizar nosso dispositivo, inibia o deslocamento quando curvas agudas eram efetuadas. No modo veículo, a orientação e o deslocamento ocorriam conjuntamente quando o usuário utilizava nosso dispositivo e técnicas, similarmente ao processo de controle de direção de um veículo. Nós aplicamos testes para determinar o modo de navegação de preferencia para uti lização de nosso dispositivo, em 52 sujeitos. Identificamos uma preferencia pelo modo de uso que se assimila a condução de um veículo. Testes estatísticos revelaram que os usuários aprenderam facilmente a usar nossa técnica para navegar em ambientes virtuais. Os usuários foram mais rápidos utilizando o modo veículo, mas o modo humano garantiu maior precisão no deslocamento no ambiente virtual. A plataforma táctil provou permi tir o uso seguro de nosso dispositivo, sendo uma solução efetiva e simples para a área. Mais de 200 pessoas testaram nosso dispositivo e técnicas: no evento Portas Abertas da UFRGS em 2013 e 2014, um evento onde são apresentados para a comunidade local os trabalhos executados na universidade; e no 3D User Interface, onde nossa técnica e dis positivos foram utilizados em conjunto com uma ferramenta de seleção de pontos numa competição. As principais contribuições do nosso trabalho são: uma nova abordagem para de tecção de imitação de caminhada, a qual permite um uso simples, com naturalidade de movimentos, expansível para utilização em áreas grandes, como espaços públicos e que efetivamente captura informações de uso e fornece orientação e velocidade para uso em ambientes virtuais ou de realidade aumentada, com uso de hardware barato
Regulation krankheitsassoziierter Signalwege durch differenziell exprimierte miRNAs im Parkinson-Zellkulturmodell
Morbus Parkinson stellt eine schwerwiegende neurodegenerative Erkrankung dar, deren Kom-plexität sowohl die Diagnosestellung als auch die Therapie bis heute erschwert. Im letzten Jahrzehnt wurden unter anderem deregulierte microRNAs (miRNAs, miRs) als vielversprechende Kandidaten für neue Diagnose- und Therapiemöglichkeiten identifiziert (Condrat et al., 2020; Hanna et al., 2019). Ziel dieser Arbeit war es daher die miRNA-Signatur in erkrankten dopaminergen Neuronen anhand eines etablierten Parkinson-Zellkulturmodells genauer zu untersuchen sowie regulatorische Zielgennetzwerke differenziell exprimierter miRNAs zu identifizieren, die zur Progression der Erkrankung beitragen könnten. Zunächst erfolgte eine Charakterisierung des zellulären Parkinson-ähnlichen Phänotyps anhand einer Transkriptomanalyse sowie anschließender Signalweganalyse, in der die Deregulation der zentralen molekularen Pathomechanismen von Morbus Parkinson im Parkinson-Zellkulturmodell auf molekularer Ebene abgebildet werden konnte. Die nachfolgende miRnom-Analyse identifizierte dreizehn miRNAs mit signifikanter Expressionsveränderung nach Induktion des Parkinson-ähnlichen Phänotyps, darunter die induzierte miR-34a-5p und reprimierte miR-7-5p. Aufgrund dieser Ergebnisse sowie weiterer Studien, die einen signifikanten Einfluss der miR-34a-5p und miR-7-5p auf die Viabilität von dopaminergen Neuronen nachweisen, wurde im weiteren Verlauf dieser Arbeit der Fokus auf diese zentralen deregulierten miRNAs gelegt, um deren Zielgennetzwerke, die zur Progression von Morbus Parkinson beitragen, umfassend zu entschlüsseln. Durch eine kombinierte in silico Zielgenvorhersage mit anschließender Anreicherungsanalyse wurden insgesamt 112 Zielgensequenzen mit miR-34a-5p-Bindestellen und 160 Zielgensequenzen mit miR-7-5p-Bindestellen aus 14 Parkinson- und Dopamin-assoziierten Signalwegen zur experimentellen Validierung ausgewählt. Mittels Hochdurchsatz-miRNA-Interaktions-Reporterassay konnte eine miRNA-Zielgeninteraktion für 73,2 % der 112 Zielgensequenzen der miR-34a-5p und 51,9 % der 160 Zielgensequenzen der miR-7-5p verifiziert werden. In der nachfolgenden Analyse des Effektes der Länge und Anzahl von miRNA-Bindestellen auf die miRNA-bedingte Regulation konnte eine verstärkte Regulation mit einer erhöhten Anzahl potenziell bindender Nukleotide erfasst werden. Die Validierung der Ergebnisse des Hochdurchsatz-miRNA-Interaktions-Reporterassay mit mutierten Reporterkonstrukten konnte 90 % der zuvor erfassten Zielgeninteraktionen der miR-34a-5p und 60 % der Zielgeninteraktionen der miR 7 5p bestätigen. Zudem konnte für ausgewählte Zielgene die zuvor mittels Hochdurchsatz-miRNA-Interaktions-Reporterassay erfasste miRNA-bedingte Regulation ebenso auf Proteinebene verifiziert werden. Die in dieser Arbeit erfassten miRNA-Zielgeninteraktionen bilden die Grundlage zur Entschlüsselung der zentralen miRNA-regulierten Pathomechanismen von Morbus Parkinson und könnten in Zukunft zur spezifischen Modulation krankheitsassoziierter Signalwege genutzt werden.Parkinson’s Disease is a severe neurodegenerative disorder whose complexity impedes diagnosis as well as therapeutic approaches until now. In the last decade, microRNAs (miRNAs, miRs) were identified as promising candidates for new diagnostic and therapeutic approaches (Condrat et al., 2020; Hanna et al., 2019). Hence, the aim of this thesis was to examine the miRNA signature in diseased dopaminergic neurons based on a well-established Parkinson’s disease cell culture model as well as to identify gene regulatory networks that could contribute to the progression of the disease. First, transcriptome analysis and subsequent pathway analysis was performed to characterize the cellular Parkinson’s disease like phenotype. In this analysis, deregulation of the central pathogenic mechanisms of Parkinson’s disease was shown on molecular level. The following miRnome analysis identified thirteen miRNAs that showed a significant expression change upon induction of Parkinson’s disease like phenotype including the upregulated miR-34a-5p and the downregulated miR 7 5p. Based on these results as well as other studies that showed a significant impact of miR-34a-5p and miR-7-5p on the viability of dopaminergic neurons, these central miRNAs were focused in the following to decipher the gene regulatory networks that contribute to the progression of Parkinson’s disease. The combination of in silico target gene prediction with subsequent enrichment analysis led to the identification of 112 target sequences with miR 34a 5p binding sites and 160 target sequences with miR-7-5p binding sites in 14 signaling pathways associated with Parkinson’s disease and dopamine. High throughput miRNA interaction reporter assay verified miRNA targeting for 73,2 % of the 112 target sequences for miR-34-5p as well as for 51,9 % of the 160 target sequences for miR-7-5p. Further examination on the effects of length and number of miRNA binding sites on miRNA-mediated regulation revealed an augmented regulation with increasing number of potentially binding nucleotides. Validation of the results obtained from the high throughput miRNA interaction reporter assay with mutated reporter constructs verified 90 % of the miRNA-target interactions for miR-34a 5p and 60 % for miR-7-5p. The miRNA-mediated regulation was also verified for selected target genes on protein level. The miRNA-target-interactions detected in this study provide a basis for deciphering the central miRNA-regulated pathogenic mechanism of Parkinson’s disease and could be used in the future for specific modulation of disease-associated signaling pathways
miR-34a-5p as molecular hub of pathomechanisms in Huntington's disease
Background Although a pivotal role of microRNA (miRNA, miR) in the pathogenesis of Huntington’s disease (HD)
is increasingly recognized, the molecular functions of miRNAs in the pathomechanisms of HD await further elucidation. One of the miRNAs that have been associated with HD is miR-34a-5p, which was deregulated in the mouse R6/2
model and in human HD brain tissues.
Methods The aim of our study was to demonstrate interactions between miR-34a-5p and HD associated genes.
By computational means we predicted 12 801 potential target genes of miR-34a-5p. An in-silico pathway analysis
revealed 22 potential miR-34a-5p target genes in the KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway
“Huntington’s disease”.
Results Using our high-throughput miRNA interaction reporter assay (HiTmIR) we identifed NDUFA9, TAF4B, NRF1,
POLR2J2, DNALI1, HIP1, TGM2 and POLR2G as direct miR-34a-5p target genes. Direct binding of miR-34a-5p to target
sites in the 3’UTRs of TAF4B, NDUFA9, HIP1 and NRF1 was verifed by a mutagenesis HiTmIR assay and by determining
endogenous protein levels for HIP1 and NDUFA9. STRING (Search Tool for the Retrieval of Interacting Genes/Proteins)
analysis identifed protein–protein interaction networks associated with HD like “Glutamine Receptor Signaling Pathway” and “Calcium Ion Transmembrane Import Into Cytosol”.
Conclusion Our study demonstrates multiple interactions between miR-34a-5p and HD associated target genes and
thereby lays the ground for future therapeutic interventions using this miRNA
Induction of the Endoplasmic-Reticulum-Stress Response: MicroRNA-34a Targeting of the IRE1α-Branch
Neurodegenerative disorders such as Alzheimer’s disease (AD) and Parkinson’s disease
(PD) are characterized by the accumulation of misfolded proteins in the endoplasmic reticulum (ER)
and the unfolded protein response (UPR). Modulating the UPR is one of the major challenges to
counteract the development of neurodegenerative disorders and other diseases with affected UPR.
Here, we show that miR-34a-5p directly targets the IRE1α branch of the UPR, including the genes BIP,
IRE1α, and XBP1. Upon induction of ER stress in neuronal cells, miR-34a-5p overexpression impacts
the resulting UPR via a significant reduction in IRE1α and XBP1s that in turn leads to decreased
viability, increased cytotoxicity and caspase activity. The possibility to modify the UPR signaling
pathway by a single miRNA that targets central genes of the IRE1α branch offers new perspectives
for future therapeutic approaches against neurodegeneration
A PULVERIZAÇÃO PRÉ-COLHEITA COM TIDIAZURON REDUZ O TEOR DE CÁLCIO E AUMENTA A ABERTURA CARPELAR E A INCIDÊNCIA DE PODRIDÃO CARPELAR EM FRUTOS DE MAÇÃ
Thidiazuron (TDZ; N-phenyl-N’-1,2,3- thiadiazol-5-ylureia) is a substituted phenylurea that shows strong cytokinin-like activity in plant tissues. The product is sprayed at full bloom on apple trees to increase fruit set and improve fruit growth. Besides affecting tree physiology and fruit size, TDZ might influence other aspects related to fruit quality. Treated plants normally bear malformed fruits with a more protruded distal end. This work was carried out to investigate the effects of TDZ on fruit carpel aperture, fruit shape, seed number, fruit calcium content, and moldy core (caused by several pathogens) of apples. Apple trees, cultivars Gala and Fuji, were sprayed at full bloom with TDZ at doses of 0, 5, 10, or 20 g (a.i) ha-1. TDZ caused fruit malformation and an increment of carpel aperture, reduced the concentration of calcium in the fruit skin, and increased the incidence of moldy core in ‘Gala’ (from 0 to 4%) and in ‘Fuji’ (from 29 to 42%). The increase of moldy core by TDZ in apples may be related to decreases on fruit calcium content and increases on carpel aperture.O tidiazuron (TDZ; N-phenil-N’-1,2,3-thiadiazol- 5-ilureia) é uma feniluréia substituida que apresenta forte ação citocinínica em tecidos de plantas. O produto é pulverizado em macieiras na plena floração para aumentar a frutificação efetiva e promover crescimento de frutos. Além de afetar a fisiologia das plantas e crescimento de frutos, o TDZ interfere em outros aspectos relacionados com a qualidade dos frutos. As plantas tratadas normalmente apresentam frutos deformados, com a parte distal protrusa. Este trabalho foi conduzido com o objetivo de avaliar os efeitos do TDZ na abertura carpelar, no formato dos frutos, no número de sementes, nos teores de cálcio e na incidência de podridão carpelar (causada por diversos patógenos) em maçãs. Macieiras, cultivares Gala e Fuji, foram pulverizadas na plena floração com TDZ nas doses de 0, 5, 10 e 20 g (i.a.) ha-1. O TDZ ocasionou deformação e aumento na abertura carpelar, reduziu a concentração de cálcio na película e aumentou a incidência de podridão carpelar em ‘Gala’ (de 0 para 4%) e ‘Fuji’ (de 29 para 42%). O aumento na incidência de podridão carpelar em macieiras pulverizadas com TDZ pode estar relacionado à redução nos teores de cálcio e o aumento na abertura carpelar nos frutos
miR-34a as hub of T cell regulation networks
Background: Micro(mi)RNAs are increasingly recognized as central regulators of immune cell function. While it has
been predicted that miRNAs have multiple targets, the majority of these predictions still await experimental confirmation.
Here, miR-34a, a well-known tumor suppressor, is analyzed for targeting genes involved in immune system processes of
leucocytes.
Methods: Using an in-silico approach, we combined miRNA target prediction with GeneTrail2, a web tool for Multi-omics
enrichment analysis, to identify miR-34a target genes, which are involved in the immune system process subcategory of
Gene Ontology.
Results: Out of the 193 predicted target genes in this subcategory we experimentally tested 22 target genes and
confirmed binding of miR-34a to 14 target genes including VAMP2, IKBKE, MYH9, MARCH8, KLRK1, CD11A, TRAFD1, CCR1,
PYDC1, PRF1, PIK3R2, PIK3CD, AP1B1, and ADAM10 by dual luciferase assays. By transfecting Jurkat, primary CD4+ and CD8+
T cells with miR-34a, we demonstrated that ectopic expression of miR-34a leads to reduced levels of endogenous VAMP2
and CD11A, which are central to the analyzed subcategories. Functional downstream analysis of miR-34a over-expression
in activated CD8+ T cells exhibits a distinct decrease of PRF1 secretion.
Conclusions: By simultaneous targeting of 14 mRNAs miR-34a acts as major hub of T cell regulatory networks suggesting
to utilize miR-34a as target of intervention towards a modulation of the immune responsiveness of T-cells in a broad
tumor context
Estabelecimento de índices de maturação para o ponto de colheita de frutos de caqui ‘Fuyu’
This study was carried out to establish maturity indices for harvest timing of persimmon fruit ‘Fuyu’grown in Fraiburgo, SC. ‘Fuyu’ persimmon fruits were harvested and classified at six stages of ripening in 2002 and 2003. Fruit skin color, flesh firmness, soluble solids content, titratable acidity, respiration and ethylene production were determined one day after harvest. Gradual changes on fruit skin color from green to red, reduction in flesh firmness, and increase in soluble solids content occurred as the maturation advanced. The titratable acidity did not change significantly with ripening. The rates of ethylene production and the rates ofrespiration increased significantly only in fruits harvested on overripe stage. Thus, the maturity indices for ‘Fuyu’ persimmon fruits harvested to storage and/or to transport were determined as 14,6 - 15,3% of soluble solids content, about 63 and 66N (~14 e 15lb) of flesh firmness, hue index between 73 and 66 and visual color index 4.Este estudo objetivou estabelecer índices de maturação para o ponto ideal de colheita de caqui ‘Fuyu’ cultivado em Fraiburgo, SC. Frutos de caquis ‘Fuyu’ foram colhidos e classificados em seis estádios de maturação em 2002 e 2003. Um dia após a colheita, os frutos foram analisados quanto à coloração da casca, firmeza da polpa,teor de sólidos solúveis, acidez titulável, respiração e produção de etileno. Mudanças gradativas da coloração da casca dos frutos de verde para vermelho, redução da firmeza da polpa e aumento no teor de sólidos solúveis ocorreram com o avanço da maturação. A acidez titulável não variou significativamente com o estádio de maturação. As taxas respiratória e de produção de etileno aumentaram significativamente apenas em frutos colhidos no estádio supermaduro. Os índices de maturação para colheita de caquis ‘Fuyu’ destinados ao armazenamento e/ou ao transporte a longa distância corresponderam aos teores de sólidos solúveis entre 14,6% e 15,3%, firmeza da polpa entre 63 e 66N (~14 e 15lb), índice hue entre 73 e 66 e índice visual de cor 4
Wrinkle in the plan: miR-34a-5p impacts chemokine signaling by modulating CXCL10/CXCL11/CXCR3-axis in CD4+, CD8+ T cells, and M1 macrophages
Background In 2016 the first-in-human phase I study of a miRNA-based cancer therapy with a liposomal mimic of microRNA-34a-5p (miR-34a-5p) was closed due to five immune related serious adverse events (SAEs) resulting in four patient deaths. For future applications of miRNA mimics in cancer therapy it is mandatory to unravel the miRNA effects both on the tumor tissue and on immune cells. Here, we set out to analyze the impact of miR-34a-5p over-expression on the CXCL10/CXCL11/CXCR3 axis, which is central for the development of an effective cancer control.
Methods We performed a whole genome expression analysis of miR-34a-5p transfected M1 macrophages followed by an over-representation and a protein–protein network analysis. In-silico miRNA target prediction and dual luciferase assays were used for target identification and verification. Target genes involved in chemokine signaling were functionally analyzed in M1 macrophages, CD4+ and CD8+ T cells.
Results A whole genome expression analysis of M1 macrophages with induced miR-34a-5p over-expression revealed an interaction network of downregulated target mRNAs including CXCL10 and CXCL11. In-silico target prediction in combination with dual luciferase assays identified direct binding of miR-34a-5p to the 3′UTRs of CXCL10 and CXCL11. Decreased CXCL10 and CXCL11 secretion was shown on the endogenous protein level and in the supernatant of miR-34a-5p transfected and activated M1 macrophages. To complete the analysis of the CXCL10/CXCL11/CXCR3 axis, we activated miR-34a-5p transfected CD4+ and CD8+ T cells by PMA/Ionomycin and found reduced levels of endogenous CXCR3 and CXCR3 on the cell surface.
Conclusions MiR-34a-5p mimic administered by intravenous administration will likely not only be up-taken by the tumor cells but also by the immune cells. Our results indicate that miR-34a-5p over-expression leads in M1 macrophages to a reduced secretion of CXCL10 and CXCL11 chemokines and in CD4+ and CD8+ T cells to a reduced expression of CXCR3. As a result, less immune cells will be attracted to the tumor site. Furthermore, high levels of miR-34a-5p in naive CD4+ T cells can in turn hinder Th1 cell polarization through the downregulation of CXCR3 leading to a less pronounced activation of cytotoxic T lymphocytes, natural killer, and natural killer T cells and possibly contributing to lymphocytopenia
Quantitative and time-resolved miRNA pattern of early human T cell activation
T cells are central to the immune response against
various pathogens and cancer cells. Complex networks of transcriptional and post-transcriptional
regulators, including microRNAs (miRNAs), coordinate the T cell activation process. Available miRNA
datasets, however, do not sufficiently dissolve the
dynamic changes of miRNA controlled networks
upon T cell activation. Here, we established a quantitative and time-resolved expression pattern for the
entire miRNome over a period of 24 h upon human Tcell activation. Based on our time-resolved datasets,
we identified central miRNAs and specified common miRNA expression profiles. We found the most
prominent quantitative expression changes for miR155-5p with a range from initially 40 molecules/cell to
1600 molecules/cell upon T-cell activation. We established a comprehensive dynamic regulatory network
of both the up- and downstream regulation of miR155. Upstream, we highlight IRF4 and its complexes
with SPI1 and BATF as central for the transcriptional
regulation of miR-155. Downstream of miR-155-5p,
we verified 17 of its target genes by the time-resolved
data recorded after T cell activation. Our data provide comprehensive insights into the range of stimulus induced miRNA abundance changes and lay the
ground to identify efficient points of intervention for
modifying the T cell response
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