Element-1 Silencing Transcription Factor Research Articles

Issue Information

Journal of NeurochemistryVolume 165, Issue 5 p. 623-624 ISSUE INFORMATIONFree Access Issue Information First published: 30 May 2023 https://doi.org/10.1111/jnc.15633 Read the full article: ‘Neuron-restrictive silencer factor/repressor element 1-silencing transcription factor (NRSF/REST) controls spatial K+ buffering in primary cortical astrocytes’ by E. Centonze, A. Marte, M. Albini, A. Rocchi, F. Cesca, M. Chiacchiaretta, T. Floss, P. Baldelli, S. Ferroni, F. Benfenati and P. Valente (J. Neurochem. vol. 165 (5), pp. 701–721) on doi:10.1111/jnc.15755 AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Graphical Abstract Front cover Neuron-restrictive silencer factor/repressor element 1 (RE1)-silencing transcription factor (NRSF/REST) is a transcriptional repressor of a large cluster of neural genes containing RE1 motifs in their promoter region. NRSF/REST is ubiquitously expressed in non-neuronal cells, including astrocytes, while it is downregulated during neuronal differentiation. While neuronal NRSF/REST homeostatically regulates intrinsic excitability and synaptic transmission, the role of the high NRSF/REST expression levels in the homeostatic functions of astrocytes is poorly understood. Here, we investigated the functional consequences of NRSF/REST deletion in primary cortical astrocytes derived from NRSF/REST conditional knockout mice (KO). We found that NRSF/REST KO astrocytes displaya markedly reduced activity of inward rectifying K+ channels subtype 4.1 (Kir4.1) underlying spatial K+ buffering, associated with decreased expression and activity of the glutamate transporter-1 (GLT-1) responsible for glutamate uptake. The data indicate that astrocytic NRSF/REST directly participates in neural circuit homeostasis by regulating intrinsic excitability and excitatory transmission and that its dysfunctions may contribute to the pathogenesis of neurological disorders. Image content GFAP immunostaining (red) in Rest-KO astrocytes bearing nuclear GFP (green) staining as reporter of Cre-transduction. Read the full article ‘Neuron-restrictive silencer factor/repressor element 1-silencing transcription factor (NRSF/REST) controls spatial K+ buffering in primary cortical astrocytes’ by E. Centonze, A. Marte, M. Albini, A. Rocchi, F. Cesca, M. Chiacchiaretta, T. Floss, P. Baldelli, S. Ferroni, F. Benfenati and P. Valente (J. Neurochem. vol. 165 (5), pp. 701–721) on doi:10.1111/jnc.15755 Volume165, Issue5June 2023Pages 623-624 RelatedInformation

Neuron-restrictive silencer factor/repressor element 1-silencing transcription factor (NRSF/REST) controls spatial K+ buffering in primary cortical astrocytes.

Neuron-restrictive silencer factor/repressor element 1 (RE1)-silencing transcription factor (NRSF/REST) is a transcriptional repressor of a large cluster of neural genes containing RE1 motifs in their promoter region. NRSF/REST is ubiquitously expressed in non-neuronal cells, including astrocytes, while it is down-regulated during neuronal differentiation. While neuronal NRSF/REST homeostatically regulates intrinsic excitability and synaptic transmission, the role of the high NRSF/REST expression levels in the homeostatic functions of astrocytes is poorly understood. Here, we investigated the functional consequences of NRSF/REST deletion in primary cortical astrocytes derived from NRSF/REST conditional knockout mice (KO). We found that NRSF/REST KO astrocyte displayed a markedly reduced activity of inward rectifying K+ channels subtype 4.1 (Kir4.1) underlying spatial K+ buffering that was associated with a decreased expression and activity of the glutamate transporter-1 (GLT-1) responsible for glutamate uptake by astrocytes. The effects of the impaired astrocyte homeostatic functions on neuronal activity were investigated by co-culturing wild-type hippocampal neurons with NRSF/REST KO astrocytes. Interestingly, neurons experienced increased neuronal excitability at high firing rates associated with decrease after hyperpolarization and increased amplitude of excitatory postsynaptic currents. The data indicate that astrocytic NRSF/REST directly participates in neural circuit homeostasis by regulating intrinsic excitability and excitatory transmission and that dysfunctions of NRSF/REST expression in astrocytes may contribute to the pathogenesis of neurological disorders.

NRSF/REST regulates the mTOR signaling pathway in oral cancer cells.

The neuron-restrictive silencer factor/repressor element 1-silencing transcription factor (NRSF/REST) was originally discovered as a transcriptional repressor of neuronal genes in non-neuronal cells. However, it was recently reported to be abundantly expressed in several types of aggressive cancer cells, as well as in mature neurons. In the present study, the role of NRSF/REST in the human oral squamous cell carcinoma (SCC) KB cell line was evaluated. NRSF/REST was expressed at a higher level in KB cells when compared with that in normal human oral keratinocytes (NHOKs). Knockdown of NRSF/REST by siRNA reduced cell viability only in KB cells in a time-dependent manner, and this effect was due to the activation of apoptosis components and DNA fragmentation. In addition, knockdown of NRSF/REST disrupted the mTOR signaling pathway which is a key survival factor in many types of cancer cells. For example, the phosphorylation of elF4G, elF4E and 4E-BP1 was significantly reduced in the KΒ cells upon NRSF/REST knockdown. These results imply that NRSF/REST plays an important role in the survival of oral cancer cells by regulating the mTOR signaling pathway.

Abstract B5: Identification of a role for REST in promoting preneoplastic events in a novel genetically engineered mouse model

Abstract Medulloblastoma is a pediatric cerebellar tumor that arises from undifferentiated neuronal stem/progenitor cells (NSCs). The Repressor Element-1 (RE1) Silencing Transcription Factor (REST) negatively regulates neurogenesis by repressing numerous genes involved in terminal neuronal differentiation. We previously showed that REST levels were abnormally elevated in medulloblastoma samples and that this was associated with poor prognosis for patients. Previous studies from two groups including ours showed that REST knockdown in human tumor cells blocked their tumorigenic potential in mouse orthotopic models, suggesting that REST was required for tumor maintenance. In addition, constitutively elevated expression of REST in neural progenitors in the context of Myc overexpression promoted tumorigenesis in the murine brain, implicating REST in tumor progression. However, a role for REST in tumor initiation has not been demonstrated. To examine if elevated REST expression in neuronal progenitors was sufficient to promote pre-neoplastic events such as proliferation, delayed differentiation and genetic instability, we generated a novel transgenic (Tg) mouse model in which human REST Tg expression could be conditionally elevated in the post-natal cerebellar progenitor cells. These studies revealed that cerebellar progenitors harvested from REST Tg mice, had sustained neurosphere formation and proliferation potential compared to progenitors from age-matched wild type littermates. Progenitors from REST Tg mice also exhibited substantially decreased expression of REST target neuronal differentiation genes such as Syn1 and SCG10 and displayed delayed onset of neurogenesis compared to wild type controls. Interestingly, progenitors with elevated REST expression had significantly perturbed telomere homeostasis associated with altered telomerase levels and increased genomic instability compared to wild type controls. The above findings were recapitulated in vivo where cerebella from REST Tg mice exhibited prolonged Ki-67 staining accompanied by lack of differentiation and accumulation of genetic instability. Furthermore, REST mediated genetic instability was associated with increased sensitivity to DNA damaging reagents such as etoposide compared to normal wild type progenitors. Thus, we provide the first demonstration of a role for elevated REST expression in neural progenitors in promoting tumor initiating events such as hyperproliferation, blockade of differentiation and telomere defects. We also show that the genetic instability contributes to the accelerated response of these cells to clinically relevant DNA damage-inducing agents. These observations may have therapeutic implications for high REST medulloblastomas. Citation Format: Tara Dobson, Ellen Busschers, Pete Taylor, Julianne Humphries, Sadhan Majumder, Vidya Gopalakrishnan. Identification of a role for REST in promoting preneoplastic events in a novel genetically engineered mouse model. [abstract]. In: Proceedings of the AACR Special Conference on Pediatric Cancer at the Crossroads: Translating Discovery into Improved Outcomes; Nov 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;74(20 Suppl):Abstract nr B5.

The Cell and Molecular Biology of Neurodegenerative Diseases: An Overview

The Cell and Molecular Biology of Neurodegenerative Diseases: An Overview

Regulation of cholinergic gene expression by the neuron restrictive silencer factor/repressor element-1 silencing transcription factor

The role of protein kinase A in regulating transcription of the cholinergic gene locus, which contains both the vesicular acetylcholine transporter gene and the choline acetyltransferase gene, was investigated in PC12 cells and a protein kinase A deficient PC12 mutant, A126.1B2 in which transcription of the locus is reduced. The site of action of protein kinase A was localized to a neuron restrictive silencer element/repressor element-1 (NRSE/RE-1) within the upstream region of the cholinergic gene locus. The neuron restrictive silencer factor/repressor element-1 silencing transcription factor (NRSF/REST), the transcription factor which binds to NRSE/RE-1, was expressed at similar levels in both PC12 and A126.1B2. Although nuclear extracts containing NRSF/REST from A126.1B2 exhibited binding to NRSE/RE-1, nuclear extracts from PC12 cells did not. The NRSF/REST isoform repressor element-1 silencing transcription factor-4 (REST4) was found to be expressed in PC12 cells, but not in the protein kinase A deficient PC12 cell line. REST4 inhibited the binding of NRSF/REST to NRSE/RE-1 as determined by gel mobility shift assays. Co-immunoprecipitation was used to demonstrate interaction between NRSF/REST and REST4. Expression of recombinant REST4 in the protein kinase A deficient PC12 cell line was sufficient to transcriptionally activate the cholinergic gene locus. Thus in PC12 cells protein kinase A promotes the production of REST4, which in turn de-represses of the cholinergic gene locus by inactivating the transcription repressor NRSF/REST.

Role of Zinc Finger Domains of the Transcription Factor Neuron-restrictive Silencer Factor/Repressor Element-1 Silencing Transcription Factor in DNA Binding and Nuclear Localization

The transcription factor neuron-restrictive silencer factor/repressor element-1 (RE-1) silencing transcription factor (NRSF/REST) contains nine zinc finger domains and binds to the DNA element, neuron-restrictive silencer element/repressor element-1. REST4, a C-terminally truncated form of NRSF/REST, contains the five N-terminal zinc fingers and binds weakly to DNA yet is transported into the nucleus. To study the contribution of zinc fingers 6-8 to DNA binding, each was mutated. A mutation in zinc finger 6 or 8 had little effect; however, mutation of zinc finger 7 diminished DNA binding. Mutations in any two of these zinc fingers eliminated DNA binding. The contribution of zinc fingers 2-5 to nuclear targeting was studied. Deletion of zinc finger 5 prevented nuclear targeting. Mutations in zinc finger 2, 4, or 5 did not abolish nuclear targeting. However, a zinc finger 3 mutation together with a zinc finger 2 mutation localized to the nuclear envelope. A zinc finger 3 mutation alone or in combination with a zinc finger 4 or 5 mutation produced a punctate nuclear distribution. These results suggest the presence of signals for nuclear targeting, for nuclear entry, and for release from the translocation machinery within zinc fingers 2-5 of REST4.