MicroRNA Expression Profiling of the Porcine Developing Brain

BACKGROUND: MicroRNAs are small, non-coding RNA molecules that regulate gene expression at the post-transcriptional level and play an important role in the control of developmental and physiological processes. In particular, the developing brain contains an impressive diversity of microRNAs. Most microRNA expression profiling studies have been performed in human or rodents and relatively limited knowledge exists in other mammalian species. The domestic pig is considered to be an excellent, alternate, large mammal model for human-related neurological studies, due to its similarity in both brain development and the growth curve when compared to humans. Considering these similarities, studies examining microRNA expression during porcine brain development could potentially be used to predict the expression profile and role of microRNAs in the human brain. METHODOLOGY/PRINCIPAL FINDINGS: MicroRNA expression profiling by use of microRNA microarrays and qPCR was performed on the porcine developing brain. Our results show that microRNA expression is regulated in a developmentally stage-specific, as well as a tissue-specific manner. Numerous developmental stage or tissue-specific microRNAs including, miR-17, miR-18a, miR-29c, miR-106a, miR-135a and b, miR-221 and miR-222 were found by microarray analysis. Expression profiles of selected candidates were confirmed by qPCR. CONCLUSIONS/SIGNIFICANCE: The differential expression of specific microRNAs in fetal versus postnatal samples suggests that they likely play an important role in the regulation of developmental and physiological processes during brain development. The data presented here supports the notion that microRNAs act as post-transcriptional switches which may regulate gene expression when required

Kuvaavat piensatelliittitutkat kaukokartoitussovelluksissa

Space assets have become more affordable due to miniaturization of sensor and satellite platform technology, which allows significant reduction in launch, operation and development costs. The first wave of new, radically smaller Earth Observation (EO) satellites was produced to enable real-time imaging with optical instruments and microwave remote sensing has been following the same trends. Imaging radar, such as SAR data, can be acquired in nearly all weather, day and seasonal conditions. Microwave instruments are more effective particularly over northern and polar regions, which are frequently covered by clouds. The SAR has also ability to penetrate canopy to certain extend and can provide information of the built environment. Recently appeared affordable small SAR satellites can increase temporal resolution of spaceborne imaging, enabling new application areas, however the imaging capabilities or constellation performance of such new SAR instruments remain relatively unknown. The aim of this study is to provide background and overview to the new small satellite SAR constellation missions, their imaging capabilities, performance, data quality and application examples by comparing selected three missions in this category, from which one, data was acquired for further image analysis. Also, the relationship of small satellite SAR missions towards their larger counterparts is examined. A particular focus is to assess the potential of the imagery of a new SAR data provider, Iceye, in relation to European Space Agency (ESA) instrument, Sentinel-1. Small satellites equipped with SAR sensors clearly create new opportunities for applications, enabled by the increased temporal resolution. These applications are largely, in the field of monitoring man-made objects and structures, especially in the surveillance sector, due to the properties of frequency bands used in the SAR sensors.Satelliitit ovat tulleet kohtuuhintaisiksi sensori- ja alustateknologian pienentymisen myötä, mikä mahdollistaa merkittävän vähennyksen laukaisu-, käyttö- ja kehittämiskustannuksissa. Uusien, radikaalisti pienempien Earth Observation (EO) -satelliittien ensimmäinen aalto tuotettiin mahdollistamaan reaaliaikainen kuvaus optisilla instrumenteilla ja mikroaaltokaukokartoitus on seurannut samoja suuntauksia. Kuvantava tutka, kuten SAR, voi operoida lähes kaikissa sää-, päivä- ja kausiolosuhteissa. Mikroaaltosensorit ovat tehokkaampia erityisesti pohjoisilla ja napa-alueilla, jotka ovat usein pilvien peittämiä. SAR:lla on myös kyky läpäistä kasvien latvuskerrosta tietylle ulottuvuudelle ja se voi tarjota tietoa rakennetusta ympäristöstä. Äskettäin ilmestyneet edulliset pienet SAR-satelliitit voivat lisätä avaruuskaukokartoituksen ajallista erotuskykyä, mahdollistamalla uusia sovellusalueita, mutta tällaisten uusien SAR-instrumenttien kuvantamisominaisuudet tai konstellaatioiden tehokkuus ovat edelleen suhteellisen tuntemattomia. Tämän tutkimuksen tarkoituksena on antaa taustaa ja yleiskatsaus uusiin SAR-piensatelliittikonstellaatioihin, niiden kuvantamisominaisuuksiin, suorituskykyyn, kuvanlaatuun ja sovellusalueisiin vertaamalla valittuja kolmea, tähän kategoriaan kuuluvaa missiota, joista yhdestä hankittiin SAR-kuvia jatkotarkastelua varten. Lisäksi tarkastellaan pienten SAR-satelliittimissioiden suhdetta suurempiin. Erityisenä tavoitteena on arvioida uuden SAR-kuvien tuottajan, Iceyen, mahdollisuuksia suhteessa Euroopan avaruusjärjestön (ESA) Sentinel-1 satelliittiin. Pienet SAR-sensoreilla varustetut satelliitit luovat selkeästi uusia mahdollisuuksia sovelluksille, jotka lisääntynyt ajallinen erotuskyky mahdollistaa. Nämä sovellukset ovat suurelta osin ihmisen tekemien kohteiden ja rakenteiden seurannassa, erityisesti valvontasektorilla, SAR-sensoreissa käytettävien taajuuskaistojen ominaisuuksien vuoksi

Cell biology:MicroRNA expression in zebrafish embryonic development

MicroRNAs (miRNAs) are small noncoding RNAs, about 21 nucleotides in length, that can regulate gene expression by base-pairing to partially complementary mRNAs. Regulation by miRNAs can play essential roles in embryonic development. We determined the temporal and spatial expression patterns of 115 conserved vertebrate miRNAs in zebrafish embryos by microarrays and by in situ hybridizations, using locked-nucleic acid-modified oligonucleotide probes. Most miRNAs were expressed in a highly tissue-specific manner during segmentation and later stages, but not early in development, which suggests that their role is not in tissue fate establishment but in differentiation or maintenance of tissue identity

MicroRNA-219 modulates NMDA receptor-mediated neurobehavioral dysfunction

N-methyl-d-aspartate (NMDA) glutamate receptors are regulators of fast neurotransmission and synaptic plasticity in the brain. Disruption of NMDA-mediated glutamate signaling has been linked to behavioral deficits displayed in psychiatric disorders such as schizophrenia. Recently, noncoding RNA molecules such as microRNAs (miRNAs) have emerged as critical regulators of neuronal functions. Here we show that pharmacological (dizocilpine) or genetic (NR1 hypomorphism) disruption of NMDA receptor signaling reduces levels of a brain-specific miRNA, miR-219, in the prefrontal cortex (PFC) of mice. Consistent with a role for miR-219 in NMDA receptor signaling, we identify calcium/calmodulin-dependent protein kinase II γ subunit (CaMKIIγ), a component of the NMDA receptor signaling cascade, as a target of miR-219. In vivo inhibition of miR-219 by specific antimiR in the murine brain significantly modulated behavioral responses associated with disrupted NMDA receptor transmission. Furthermore, pretreatment with the antipsychotic drugs haloperidol and clozapine prevented dizocilpine-induced effects on miR-219. Taken together, these data support an integral role for miR-219 in the expression of behavioral aberrations associated with NMDA receptor hypofunction

Loss of microRNA cluster miR-29a/b-1 in sporadic Alzheimer's disease correlates with increased BACE1/β-secretase expression

Although the role of APP and PSEN genes in genetic Alzheimer's disease (AD) cases is well established, fairly little is known about the molecular mechanisms affecting Aβ generation in sporadic AD. Deficiency in Aβ clearance is certainly a possibility, but increased expression of proteins like APP or BACE1/β-secretase may also be associated with the disease. We therefore investigated changes in microRNA (miRNA) expression profiles of sporadic AD patients and found that several miRNAs potentially involved in the regulation of APP and BACE1 expression appeared to be decreased in diseased brain. We show here that miR-29a, -29b-1, and -9 can regulate BACE1 expression in vitro. The miR-29a/b-1 cluster was significantly (and AD-dementia-specific) decreased in AD patients displaying abnormally high BACE1 protein. Similar correlations between expression of this cluster and BACE1 were found during brain development and in primary neuronal cultures. Finally, we provide evidence for a potential causal relationship between miR-29a/b-1 expression and Aβ generation in a cell culture model. We propose that loss of specific miRNAs can contribute to increased BACE1 and Aβ levels in sporadic AD

Potential pitfalls in microRNA profiling

MicroRNAs (miRNAs) are small, noncoding RNAs that post-transcriptionally influence a wide range of cellular processes such as the host response to viral infection, innate immunity, cell cycle progression, migration and apoptosis through the inhibition of target mRNA translation. Due to the growing number of microRNAs and identification of their functional roles, miRNA profiling of many different sample types has become more expansive, especially with relevance to disease signatures. Here, we address some of the advantages and potential pitfalls of the currently available methods for miRNA expression profiling. Some of the topics discussed include isomiRNAs, comparison of different profiling platforms, normalization strategies and issues with regard to sample preparation and experimental analyses