neuroscience

How the human brain and human cognitive abilities evolved in less than six million years has long puzzled scientists. A new study conducted by scientists in China and Germany, and published December 6 in the online, open-access journal PLoS Biology, now provides a possible explanation by showing that activity levels of genes in the human brain during development changed substantially compared to chimpanzees and macaques. What’s more, these changes might be caused by a handful of key regulatory microRNAs.

The authors studied gene activity in human, chimpanzee and macaque brains across their lifetimes. Starting from newborns, they investigated two brain regions; the cerebellum, which is responsible for motor activity, and the prefrontal cortex, which has roles in more complex behavior such as social interactions or abstract thinking. They first studied the simple gene activity differences between species that are seen at all ages. Although many genes show such simple differences, there was no disparity in numbers of these differences between the human and the chimpanzee evolutionary lineages. Moreover, most of these differences were observed in [click to continue…]

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The hippocampus is a part of the brain critically involved in memory formation and spatial navigation. Shinohara et al. (2011,) used deep sequencing for  miRNA profiling of multiple samples of the mature male rat hippocampal CA3 region. According to their study, the let-7 family miRNA represents about half of the small RNA cDNA library. Major let-7 family miRNAs are  let-7c (23%), let-7a (9%), let-7f (9%), and let-7b (7%). The authors found miR134, a miRNA previously reported to be related to synaptic plasticity and morphology, only modestly expressed (~0.05%). The miRNA profiles of the left and right hippocampi were similar.  The sequence data derived from 3 pooled data sets and each data set contained corresponding left and right hippocampal CA3 samples. This study is one of the fewest studies in which miRNA expression profiles were quantitatively assessed in a specific region of the brain. The raw sequence reads and cross-mapped results are available in the DDJB sequence archive with the accession number DRA000379 (http://trace.ddbj.nig.ac.jp/DRASearch/submission?acc=DRA000379).

miRNA profiling of bilateral rat hippocampal CA3 by deep sequencing.
Shinohara Y, Yahagi K, Kawano M, Nishiyori H, Kawazu C, Suzuki N, Manabe RI, Hirase H.
Biochem Biophys Res Commun. 2011 May 13. [Epub ahead of print]
PMID:  21575607 [PubMed - as supplied by publisher]
http://www.ncbi.nlm.nih.gov/pubmed/21575607

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Researchers at Heidelberg University used a combination of expression profiling of miRNAs and subsequent functional inhibitory screening in primary hippocampal neurons to identify miRNAs in the synaptodendritic compartment that function during synaptic development. MicroRNA microarrays identified ten mature miRNAs that were enriched and four mature miRNAs that were strongly depleted in synaptosomes compared with whole forebrain. Northern blot analysis on selected miRNAs confirmed the microarray results. Subsequent functional screening identified miR-138 as a negative regulator of dendritic spine size and revealed that mRNA encoding acyl-protein thioesterase 1 (APT1) is a miR-138 target in neurons.

Siegel G, Obernosterer G, Fiore R, Oehmen M, Bicker S, Christensen M, Khudayberdiev S, Leuschner PF, Busch CJ, Kane C, Hübel K, Dekker F, Hedberg C, Rengarajan B, Drepper C, Waldmann H, Kauppinen S, Greenberg ME, Draguhn A, Rehmsmeier M, Martinez J, Schratt GM. (2009) A functional screen implicates microRNA-138-dependent regulation of the depalmitoylation enzyme APT1 in dendritic spine morphogenesis. Nat Cell Biol 11(6), 705-16. [abstract]

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The discovery of microRNA as an additional regulatory mechanism has been a revolution to the field of Developmental Biology. While early research has focused on the identification of miRNAs using a combination of experimental and computational techniques, subsequent studies have focused on identification of miRNA-target mRNA pairs as a means of identifying regulatory networks. It has been shown that the relationship between messenger RNA and microRNA (often an inverse relationship) plays a large role in cell functionality, especially in the early stages of cell development. [click to continue…]

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MicroRNA at SFN 2009

by Chris on October 7, 2009

in Conferences

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Below is a list of the sessions/posters at the upcoming Society for Neuroscience Conference that will feature the topic of microRNA:

Sat, Oct 17, 3:00 ‐4:00 PM 29.19/A54 ‐The role of micrornas in midbrain dopaminergic neurogenesis

*A. M. ANDEREGG, B. A. YUN, M. JOKSIMOVIC, R. B. AWATRAMANI; Neurol., Northwestern Univ., Chicago, IL

Poster 29. Neurogenesis and Gliogenesis: Proliferation I Sat, Oct 17, 1:00 ‐5:00 PM

Sat, Oct 17, 2:00 ‐3:00 PM 30.10/B15 ‐let‐7 and Lin‐28: A feedback loop controlling neural stem cell commitment

*A. RYBAK1, H. FUCHS2, E. CUEVAS1, R. NITSCH1, F. WULCZYN1; 1Ctr. Anat, Berlin, Germany; 2Ctr. Anat, Berlin, Germany

Poster 30. Adult Neurogenesis and Stem Cells Sat, Oct 17, 1:00 ‐5:00 PM

Sat, Oct 17, 2:00 ‐3:00 PM 31.2/B28 ‐MicroRNAs regulate oligodendrocyte precursor cell differentiation and the expression of myelin­specific proteins

*C. E. PEDRAZA1, W. B. MACKLIN2; 1Neurosciences, Cleveland Clin., Beachwood, OH; 2Cell and Developmental Biol., Univ. of Colorado Denver Med. Sch., Denver, CO

Poster 31. Oligodendrocyte Differentiation Sat, Oct 17, 1:00 ‐5:00 PM

Sat, Oct 17, 2:00 ‐3:00 PM 31.10/B36 ‐Identification of microRNAs that functionally regulate oligodendrocyte differentiation

*J. C. DUGAS1, T. L. CUELLAR2, A. SCHOLZE1, B. ASON2, A. IBRAHIM1, B. EMERY1, J. L. ZAMANIAN1, L. C. FOO1, M. T. MCMANUS2, B. A. BARRES1; 1Dept Neurobiol, Stanford Univ., Stanford, CA; 2Microbiology and Immunol., Univ. of California, San Francisco, San Francisco, CA [click to continue…]

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