A single miRNA and miRNA sponge expression system for efficient modulation of miR-223 availability in mammalian cells.

BACKGROUND: Hundreds of microRNAs (miRNAs), comprising small non-coding RNAs of 20-24 nucleotides, have been discovered, although the entirety of their biological functions is poorly understood. Overexpression or suppression approaches are commonly performed to investigate the function of specific miRNAs. In the present study, we focused on generating a lentiviral vector-based strategy that enables hsa-miR-223-3p (miR-223) overexpression and suppression in the target cells for functional analysis of this miRNA easily and rapidly. METHODS: The sequence that gives rise to miR-223 and the sequence generating the sponge RNA with four binding sites for miR-223 were cloned in pLVX-shRNA2 vector. The functionality of the vector to overexpress miR-223 was evaluated by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) assays, whereas the post-transcriptional regulation exerted by miR-223 was evaluated by luciferase reporter assays in AD-293 cells. The anti-miR-223 sponge activity with one binding site for miR-223 (pmCherry-anti-miR-223) was confirmed by qRT-PCR and the restoration of its target (IKKα) was evaluated by western blot assays in Jurkat cells. RESULTS: The pLVX-miR-223 vector is functional for over-expressing miR-223 and regulates the mRNA of MDR1/ABCB1 at the post-transcriptional level in AD-293 cells. The anti-miR-223 sponge with one miR-223 binding site efficiently modulates the miR-223 availability and not the one with four sites. The over-expression of anti-miR-223 correlated with a decrease in the levels of miR-223 and, consequently, with an increase in the expression level of the IKKα protein in Jurkat cells. CONCLUSIONS: This single miRNA and miRNA sponge expression system specifically alters the availability of miR-223 in mammalian cells.

Preprints in biomedicine: alternative or complement to the traditional model of publication? / Preimpresiones en biomedicina: ¿alternativa o complemento al modelo tradicional de publicación?

The peer-review system has allowed the quality control of the manuscripts submitted for publication to scientific journals for over three centuries. However, due to its relative slowness and other drawbacks, some researchers, mainly in the areas of Physics and Mathematics, started some decades ago to propagate, by electronic means, manuscripts not yet submitted to a journal for formal publication. The dissemination of this practice led to the establishment of permanent repositories like ArXiv, to which preprints can be sent to be published whitou charge, allowing also the search and download of the works they contain with no payment required from the reader. In biomedical sciences, the adoption of the system has been slower than in the exact sciences and previous attempts like e-biomed, Netprints, and Nature Precedings did not prosper. A new generation of repositories like bioRXiv, inspired by ArXiv, seems to enjoy an increasing acceptance among biomedical researchers. Here, we discuss the potential role of this emerging system to establish discovery priority in biomedicine and to improve manuscripts before they are submitted to scientific journals besides other applications which could be implemented in the extent that the model becomes more popular.

La revisión por pares es un sistema que ha permitido el control de calidad de los manuscritos enviados para publicación en revistas científicas durante más de tres siglos. Sin embargo, debido a su relativa lentitud y otras desventajas, algunos investigadores (principalmente en las áreas de la física y las matemáticas) iniciaron hace algunas décadas la difusión electrónica de manuscritos aún no sometidos a una revista de publicación formal. La popularización de esta práctica condujo al establecimiento de repositorios permanentes como ArXiv, a los que es posible enviar preimpresiones de forma gratuita y que a la vez permiten la búsqueda y descarga de los trabajos que contienen sin cargo para el lector. En las ciencias biomédicas la adopción de este sistema ha sido más lenta que en las ciencias exactas e intentos previos como e-biomed, Netprints y Nature Precedings no prosperaron. Una nueva generación de repositorios como bioRXiv, inspirado en ArXiv, parece gozar de una creciente aceptación entre investigadores biomédicos. Aquí discutimos el potencial papel de este sistema emergente para establecer la primicia de descubrimientos en biomedicina y el mejoramiento de manuscritos antes de su sometimiento a revistas científicas, así como para otras aplicaciones que podrían implementarse en la medida en que el modelo se popularice.

Does the linear Sry transcript function as a ceRNA for miR-138? The sense of antisense.

Recently, the sex determining region Y ( Sry) and the cerebellar degeneration-related protein 1 ( CDR1as) RNA transcripts have been described to function as a new class of post-transcriptional regulatory RNAs that behave as circular endogenous RNA sponges for the micro RNAs (miRNAs) miR-138 and miR-7, respectively. A special feature of the Sry gene is its ability to generate linear and circular transcripts, both transcribed in the sense orientation. Here we remark that both sense (e.g. Sry RNA) and antisense (e.g. CDR1as) transcripts could circularize and behave as miRNAs sponges, and importantly, that also protein-coding segments of mRNAs could also assume this role. Thus, it is reasonable to think that the linear Sry sense transcript could additionally act as a miRNA sponge, or as an endogenous competing RNA for miR-138.