Am J Stem Cell 2012;1(3):182-195

Review Article
Specification of neural cell fate and regulation of neural stem cell proliferation by

Jacqueline T Pham, G Ian Gallicano

Department of Nursing; Department of Biochemistry and Molecular and Cellular Biology, Georgetown University,
Washington DC, USA

Received July 27, 2012; Accepted October 8, 2012; Epub November 30, 2012; Published December 10, 2012

Abstract: In the approximately 20 years since microRNAs (miRNAs) were first characterized, they have been shown
to play important roles in diverse physiologic functions, particularly those requiring coordinated changes in networks
of signaling pathways. The ability of miRNAs to silence expression of multiple gene targets hints at complex connections
that research has only begun to elucidate. The nervous system, particularly the brain, and its progenitor cells
offer opportunities to examine miRNA function due to the myriad different cell types, numerous functionally distinct
regions, and fluidly dynamic connections between them. This review aims to summarize current understanding of
miRNA regulation in neurodevelopment, beginning with miRNAs that establish a general neural fate in cells. Particular
attention is given to miR-124, the most abundant brain-specific miRNA, along with its key regulators and targets
as an example of the potentially far-reaching effects of miRNAs. These modulators and mediators enable miRNAs
to subtly calibrate cellular proliferation and differentiation. To better understand their mechanisms of action, miRNA
profiles in distinct populations and regions of cells have been examined as well as miRNAs that regulate proliferation
of stem cells, a process marked by dramatic morphological shifts in response to temporally subtle and refined
shifts in gene expression. To tease out the complex interactions of miRNAs and stem cells more accurately, future
studies will require more sensitive methods of assessing miRNA expression and more rigorous models of miRNA
pathways. Thorough characterization of similarities and differences in specific miRNAs’ effects in different species
is vital to developing better disease models and therapeutics using miRNAs. (AJSC1207001).

Keywords: MicroRNA, stem cell, neural development, neural stem cell

Address all correspondence to:
Dr. G Ian Gallicano
Department of Biochemistry and Molecular & Cellular Biology
Georgetown University, Washington DC, USA.
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