MicroRNA-9

Abstract

T he functional significance of microRNA-9 (miR-9) during evolution is evidenced by its conservation at the nucleotide level from flies to humans but not its diverse expression patterns. Recent studies in several model systems reveal that miR-9 can regulate neurogenesis through its actions in neural or non-neural cell lineages. In vertebrates, miR-9 exerts diverse cell-autonomous effects on the proliferation, migration and differentiation of neural progenitor cells by modulating different mRNA targets. In some developmental contexts, miR-9 suppresses apoptosis and is misregulated in several types of cancer cells, influencing proliferation or metastasis formation. Moreover, downregulation of miR-9 in postmitotic neurons is also implicated in some neurodegenerative diseases. Thus, miR-9 is emerging as an important regulator in development and disease through its ability to modulate different targets in a manner dependent on the developmental stage and the cellular context.

The Brain-Enriched MicroRNA miR-9-3p Regulates Synaptic Plasticity and Memory

“…It is exclusively expressed in the sensory neuron and regulates serotonin-mediated synaptic plasticity through the regulation of CREB (Rajasethupathy et al, 2009). In addition to these miRNAs, several miRNAs are reported to be highly enriched in the brain (Sempere et al, 2004), but their roles in synaptic plasticity, learning, and memory are still largely unknown.…”

“…For example, forebrain-specific disruption of Dicer1, a key RNase III enzyme for miRNA biogenesis, affected the expression of a set of brain-specific miRNAs and improved performance in learning and memory tasks in adult mice (Konopka et al, 2010). miR-134, which is specifically expressed in the brain, was shown to regulate the size of dendritic spines, excitatory synaptic transmission, and synaptic plasticity (Schratt et al, 2006;Gao et al, 2010). The role of another brain-specific miRNA, miR-124, was studied in the marine snail Aplysia californica (Rajasethupathy et al, 2009).…”

“…miRNAs are short nucleotides (ϳ22 nt) regulating the stability and translation of target mRNAs via complementary binding to 3Ј-untranslated regions (3Ј UTRs), which fine-tunes the expression of various target genes and orchestrates diverse biological processes, including proliferation, development, metabolism, apoptosis, and cell fate decision (Bartel, 2004;He and Hannon, 2004;Marcuzzo et al, 2015). There is emerging evidence suggesting that miRNAs play essential roles in synaptic plasticity and memory in both invertebrates and vertebrates (Schratt, 2009). For example, forebrain-specific disruption of Dicer1, a key RNase III enzyme for miRNA biogenesis, affected the expression of a set of brain-specific miRNAs and improved performance in learning and memory tasks in adult mice (Konopka et al, 2010).…”

Expression levels of microRNA-145 and microRNA-10b are associated with metastasis in non-small cell lung cancer

“…18 Ma et al reported that miR-9 can increase cell motility and invasiveness through directly targeting CDH1 (the Ecadherin-encoding mRNA), and the expression level of miR-9 is correlated with MYCN amplification, tumor grade, and metastatic status in breast cancer. 19 However, in our studies, miR-9 did not appear to be correlated with lymph node metastasis but instead with histology and stage in NSCLC.…”

Three years of RNA Families

“…[16][17][18] We have recently started soliciting reviews of notable miRNA families. [19][20][21] One very interesting example from this batch is from Peter Stadler's lab, 22 where an entire undergraduate lab is credited with contributing to the article. This illustrates that this series of articles can be a useful way of training research students and can also bridge views spanning research groups that have not traditionally collaborated.…”