MiRNAs are tiny non-translated RNAs of about 22 nucleotides that are capable of modulating translation. We would like to understand their role in neuronal function. This proposal will verify a series of findings that must be true to satisfy a general framework hypothesis that miRNAs are captured by a synAPtic tag to implement enduring long term potentiation. To satisfy this hypothesis we need to know whether miRNAs are (a) transcriptionally regulated and if so whether they are transcriptionally regulated following synaptic activation, (b) whether miRNAs are translocated to dendrites, (c) whether suppression of miRNAs can interfere with any of the facets of plasticity. Each of these requirements will be tested in this proposal; however additional experiments, which fall beyond the scope of this proposal, will be necessary to verify the general hypothesis including ultimately direct physiologic measurements of LTP in the context of miRNA suppression. For the studies proposed here we first need to identify specific miRNAs involved in plasticity. In the preliminary data we present our discovery of a large number of brain miRNAs. To accomplish our goals we have built the first miRNA arrays and this technological innovation will allow us to visualize the regulation of all known miRNAs in a single experiment. We will validate these arrays and use them for determining specific miRNA expression profiles related to the stage of cellular maturation as neurons undergo polarity acquisition. We will attempt to identify those miRNAs localized to dendrites. We will analyze miRNA transcriptional profiles following receptor stimulation and following direct activation of the CRE promoter. Finally we will build upon our recent technological innovation, which has extended the RNAi technique to the suppression of specific transcripts in neuronal culture. We will determine the effects of global suppression of miRNA maturation by RNAi interference targeted to Dicer. In particular, impaired neuronal polarity acquisition, synaptogenesis, and translation of specific mRNAs are possible phenotypic outcomes of Dicer suppression.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Exploratory/Developmental Grants (R21)
Project #
5R21NS046569-02
Application #
6744337
Study Section
National Institute of Neurological Disorders and Stroke Initial Review Group (NSD)
Program Officer
Mamounas, Laura
Project Start
2003-05-01
Project End
2005-04-30
Budget Start
2004-05-01
Budget End
2005-04-30
Support Year
2
Fiscal Year
2004
Total Cost
$205,438
Indirect Cost
Name
Brigham and Women's Hospital
Department
Type
DUNS #
030811269
City
Boston
State
MA
Country
United States
Zip Code
02115
Krichevsky, Anna M; Sonntag, Kai-C; Isacson, Ole et al. (2006) Specific microRNAs modulate embryonic stem cell-derived neurogenesis. Stem Cells 24:857-64
Chan, Jennifer A; Krichevsky, Anna M; Kosik, Kenneth S (2005) MicroRNA-21 is an antiapoptotic factor in human glioblastoma cells. Cancer Res 65:6029-33