Selenium Drives a Transcriptional Adaptive Program to Block Ferroptosis and Treat Stroke.

Ferroptosis, a non-apoptotic form of programmed cell death, is triggered by oxidative stress in cancer, heat stress in plants, and hemorrhagic stroke. A homeostatic transcriptional response to ferroptotic stimuli is unknown. We show that neurons respond to ferroptotic stimuli by induction of selenoproteins, including antioxidant glutathione peroxidase 4 (GPX4). Pharmacological selenium (Se) augments GPX4 and other genes in this transcriptional program, the selenome, via coordinated activation of the transcription factors TFAP2c and Sp1 to protect neurons. Remarkably, a single dose of Se delivered into the brain drives antioxidant GPX4 expression, protects neurons, and improves behavior in a hemorrhagic stroke model. Altogether, we show that pharmacological Se supplementation effectively inhibits GPX4-dependent ferroptotic death as well as cell death induced by excitotoxicity or ER stress, which are GPX4 independent. Systemic administration of a brain-penetrant selenopeptide activates homeostatic transcription to inhibit cell death and improves function when delivered after hemorrhagic or ischemic stroke.

Temporary induction of hypoxic adaptations by preconditioning fails to enhance Schwann cell transplant survival after spinal cord injury.

Hypoxic preconditioning is protective in multiple models of injury and disease, but whether it is beneficial for cells transplanted into sites of spinal cord injury (SCI) is largely unexplored. In this study, we analyzed whether hypoxia-related preconditioning protected Schwann cells (SCs) transplanted into the contused thoracic rat spinal cord. Hypoxic preconditioning was induced in SCs prior to transplantation by exposure to either low oxygen (1% O2 ) or pharmacological agents (deferoxamine or adaptaquin). All preconditioning approaches induced hypoxic adaptations, including increased expression of HIF-1α and its target genes. These adaptations, however, were transient and resolved within 24 h of transplantation. Pharmacological preconditioning attenuated spinal cord oxidative stress and enhanced transplant vascularization, but it did not improve either transplanted cell survival or recovery of sensory or motor function. Together, these experiments show that hypoxia-related preconditioning is ineffective at augmenting either cell survival or the functional outcomes of SC-SCI transplants. They also reveal that the benefits of hypoxia-related adaptations induced by preconditioning for cell transplant therapies are not universal.

Delayed Infiltration of Peripheral Monocyte Contributes to Phagocytosis and Transneuronal Degeneration in Chronic Stroke.

BACKGROUND: Mononuclear phagocytes, including monocyte-derived macrophages (MDMs) and microglia, contribute to infarct development as well as tissue repair in the postischemic brain. Here, we identify the origin and function of MDMs in the brain during poststroke repair processes. METHODS: Adult mice were subjected to transient middle cerebral artery occlusion. Longitudinal brain atrophy and secondary degeneration were evaluated during acute to recovery phases of stroke. Adoptive transfer of GFP+ splenocytes into asplenic mice was used to distinguish MDMs from resident microglia. Fluorescence beads were injected into stroked animals to examine phagocytic function. RESULTS: Progressive atrophy and neuronal degeneration in remote regions were observed in chronic stroke, which also was accompanied by MDM infiltration into the ipsilateral hemisphere. Compared with microglia, MDMs had significantly higher phagocytic activity. MDM trafficking and phagocytosis was spatiotemporally regulated with acute and prolonged infiltration into infarcted tissue, as well as delayed entry in remote areas such as the thalamus and substantia nigra. CONCLUSIONS: The stepwise and long-lasting involvement of MDMs at multiple poststroke stages shows that MDMs have a role in progressive stroke-induced injury and repair processes. These findings suggest that manipulating monocyte entry at different stroke stages may be an effective immune-based strategy to limit injury propagation in chronic stroke.

Phagocytosis converts infiltrated monocytes to microglia-like phenotype in experimental brain ischemia.

BACKGROUND: Monocyte-derived macrophages (MDMs) and microglia elicit neural inflammation and clear debris for subsequent tissue repair and remodeling. The role of infiltrating MDMs in the injured brain, however, has been controversial due to overlapping antigen expression with microglia. In this study, we define the origin and function of MDMs in cerebral ischemia. METHODS: Using adoptive transfer of GFP+ splenocytes into adult asplenic mice subjected to transient middle cerebral artery occlusion, we compared the role of CD11b+/CD45+/NK1.1-/Ly6G- MDMs and microglia in the ischemic brain. The phagocytic activities of MDMs and microglia were measured by the uptake of fluorescent beads both in vivo with mice infused with GFP+ splenocytes and ex vivo with cultures of isolated brain immune cells. RESULTS: Stroke induced an infiltration of MDMs [GFP+] into the ipsilateral hemisphere at acute (3 days) and sub-acute phases (7 days) of post-stroke. At 7 days, the infiltrating MDMs contained both CD45High and CD45Low subsets. The CD45High MDMs in the injured hemisphere exhibited a significantly higher proliferation capacity (Ki-67 expression levels) as well as higher expression levels of CD11c when compared to CD45Low MDMs. The CD45High and CD45Low MDM subsets in the injured hemisphere were approximately equal populations, indicating that CD45High MDMs infiltrating the ischemic brain changes their phenotype to CD45Low microglia-like phenotype. Studies with fluorescent beads reveal high levels of MDM phagocytic activity in the post-stroke brain, but this phagocytic activity was exclusive to post-ischemic brain tissue and was not detected in circulating monocytes. By contrast, CD45Low microglia-like cells had low levels of phagocytic activity when compared to CD45High cells. Both in vivo and ex vivo studies also show that the phagocytic activity in CD45High MDMs is associated with an increase in the CD45Low/CD45High ratio, indicating that phagocytosis promotes MDM phenotype conversion. CONCLUSIONS: This study demonstrates that MDMs are the predominant phagocytes in the post-ischemic brain, with the CD45High subset having the highest phagocytic activity levels. Upon phagocytosis, CD45High MDMs in the post-ischemic brain adopt a CD45Low phenotype that is microglia-like. Together, these studies reveal key roles for MDMs and their phagocytic function in tissue repair and remodeling following cerebral ischemia.

Aflibercept, a VEGF (Vascular Endothelial Growth Factor)-Trap, Reduces Vascular Permeability and Stroke-Induced Brain Swelling in Obese Mice.

Background and Purpose: Brain edema is an important underlying pathology in acute stroke, especially when comorbidities are present. VEGF (Vascular endothelial growth factor) signaling is implicated in edema. This study investigated whether obesity impacts VEGF signaling and brain edema, as well as whether VEGF inhibition alters stroke outcome in obese subjects. Methods: High-fat diet-induced obese mice were subjected to a transient middle cerebral artery occlusion. VEGF-A and VEGFR2 (receptor) expression, infarct volume, and swelling were measured 3 days post-middle cerebral artery occlusion. To validate the effect of an anti-VEGF strategy, we used aflibercept, a fusion protein that has a VEGF-binding domain and acts as a decoy receptor, in human umbilical vein endothelial cells stimulated with rVEGF (recombinant VEGF; 50 ng/mL) for permeability and tube formation. In vivo, aflibercept (10 mg/kg) or IgG control was administered in obese mice 3 hours after transient 30 minutes middle cerebral artery occlusion. Blood-brain barrier integrity was assessed by IgG staining and dextran extravasation in the postischemic brain. A separate cohort of nonobese (lean) mice was subjected to 40 minutes middle cerebral artery occlusion to test the effect of aflibercept on malignant infarction. Results: Compared with lean mice, obese mice had increased mortality, infarct volume, swelling, and blood-brain barrier disruption. These outcomes were also associated with increased VEGF-A and VEGFR2 expression. Aflibercept reduced VEGF-A-stimulated permeability and tube formation in human umbilical vein endothelial cells. Compared with the IgG-treated controls, mice treated with aflibercept had reduced mortality rates (40% versus 17%), hemorrhagic transformation (43% versus 27%), and brain swelling (28% versus 18%), although the infarct size was similar. In nonobese mice with large stroke, aflibercept neither improved nor exacerbated stroke outcomes. Conclusions: The study demonstrates that aflibercept selectively attenuates stroke-induced brain edema and vascular permeability in obese mice. These findings suggest the repurposing of aflibercept to reduce obesity-enhanced brain edema in acute stroke.

Odorant Sensory Input Modulates DNA Secondary Structure Formation and Heterogeneous Ribonucleoprotein Recruitment on the Tyrosine Hydroxylase and Glutamic Acid Decarboxylase 1 Promoters in the Olfactory Bulb.

Adaptation of neural circuits to changes in sensory input can modify several cellular processes within neurons, including neurotransmitter biosynthesis levels. For a subset of olfactory bulb interneurons, activity-dependent changes in GABA are reflected by corresponding changes in Glutamate decarboxylase 1 (Gad1) expression levels. Mechanisms regulating Gad1 promoter activity are poorly understood, but here we show that a conserved G:C-rich region in the mouse Gad1 proximal promoter region both recruits heterogeneous nuclear ribonucleoproteins (hnRNPs) that facilitate transcription and forms single-stranded DNA secondary structures associated with transcriptional repression. This promoter architecture and function is shared with Tyrosine hydroxylase (Th), which is also modulated by odorant-dependent activity in the olfactory bulb. This study shows that the balance between DNA secondary structure formation and hnRNP binding on the mouse Th and Gad1 promoters in the olfactory bulb is responsive to changes in odorant-dependent sensory input. These findings reveal that Th and Gad1 share a novel transcription regulatory mechanism that facilitates sensory input-dependent regulation of dopamine and GABA expression.SIGNIFICANCE STATEMENT Adaptation of neural circuits to changes in sensory input can modify several cellular processes within neurons, including neurotransmitter biosynthesis levels. This study shows that transcription of genes encoding rate-limiting enzymes for GABA and dopamine biosynthesis (Gad1 and Th, respectively) in the mammalian olfactory bulb is regulated by G:C-rich regions that both recruit heterogeneous nuclear ribonucleoproteins (hnRNPs) to facilitate transcription and form single-stranded DNA secondary structures associated with repression. hnRNP binding and formation of DNA secondary structure on the Th and Gad1 promoters are mutually exclusive, and odorant sensory input levels regulate the balance between these regulatory features. These findings reveal that Th and Gad1 share a transcription regulatory mechanism that facilitates odorant-dependent regulation of dopamine and GABA expression levels.

Selective repression of Notch pathway target gene transcription.

The Notch signaling pathway regulates metazoan development, in part, by directly controlling the transcription of target genes. For a given cellular context, however, only subsets of the known target genes are transcribed when the pathway is activated. Thus, there are context-dependent mechanisms that selectively maintain repression of target gene transcription when the Notch pathway is activated. This review focuses on molecular mechanisms that have been recently reported to mediate selective repression of Notch pathway target gene transcription. These mechanisms are essential for generating the complex spatial and temporal expression patterns of Notch target genes during development.

G-quadruplex regulation of neural gene expression.

G-quadruplexes are four-stranded helical nucleic acid structures characterized by stacked tetrads of guanosine bases. These structures are widespread throughout mammalian genomic DNA and RNA transcriptomes, and prevalent across all tissues. The role of G-quadruplexes in cancer is well-established, but there has been a growing exploration of these structures in the development and homeostasis of normal tissue. In this review, we focus on the roles of G-quadruplexes in directing gene expression in the nervous system, including the regulation of gene transcription, mRNA processing, and trafficking, as well as protein translation. The role of G-quadruplexes and their molecular interactions in the pathology of neurological diseases is also examined. Outside of cancer, there has been only limited exploration of G-quadruplexes as potential intervention targets to treat disease or injury. We discuss studies that have used small-molecule ligands to manipulate G-quadruplex stability in order to treat disease or direct neural stem/progenitor cell proliferation and differentiation into therapeutically relevant cell types. Understanding the many roles that G-quadruplexes have in the nervous system not only provides critical insight into fundamental molecular mechanisms that control neurological function, but also provides opportunities to identify novel therapeutic targets to treat injury and disease.

Differential regulation of dopaminergic gene expression by Er81.

A recent study proposed that differentiation of dopaminergic neurons requires a conserved "dopamine motif" (DA-motif) that functions as a binding site for ETS DNA binding domain transcription factors. In the mammalian olfactory bulb (OB), the expression of a set of five genes [including tyrosine hydroxylase (Th)] that are necessary for differentiation of dopaminergic neurons was suggested to be regulated by the ETS-domain transcription factor ER81 via the DA-motif. To investigate this putative regulatory role of ER81, expression levels of these five genes were compared in both olfactory bulbs of adult wild-type mice subjected to unilateral naris closure and the olfactory bulbs of neonatal Er81 wild-type and mutant mice. These studies found that ER81 was necessary only for Th expression and not the other cassette genes. Chromatin immunoprecipitation (ChIP) and electrophoretic mobility shift assays (EMSA) experiments showed that ER81 bound directly to a consensus binding site/DA-motif in the rodent Th proximal promoter. However, the ER81 binding site/DA-motif in the Th proximal promoter is poorly conserved in other mammals. Both ChIP assays with canine OB tissue and EMSA experiments with the human Th proximal promoter did not detect ER81 binding to the Th DA-motif from these species. These results suggest that regulation of Th expression by the direct binding of ER81 to the Th promoter is a species-specific mechanism. These findings indicate that ER81 is not necessary for expression of the OB dopaminergic gene cassette and that the DA-motif is not involved in differentiation of the mammalian OB dopaminergic phenotype.

HIF1α stabilization in hypoxia is not oxidant-initiated.

Hypoxic adaptation mediated by HIF transcription factors requires mitochondria, which have been implicated in regulating HIF1α stability in hypoxia by distinct models that involve consuming oxygen or alternatively converting oxygen into the second messenger peroxide. Here, we use a ratiometric, peroxide reporter, HyPer to evaluate the role of peroxide in regulating HIF1α stability. We show that antioxidant enzymes are neither homeostatically induced nor are peroxide levels increased in hypoxia. Additionally, forced expression of diverse antioxidant enzymes, all of which diminish peroxide, had disparate effects on HIF1α protein stability. Moreover, decrease in lipid peroxides by glutathione peroxidase-4 or superoxide by mitochondrial SOD, failed to influence HIF1α protein stability. These data show that mitochondrial, cytosolic or lipid ROS were not necessary for HIF1α stability, and favor a model where mitochondria contribute to hypoxic adaptation as oxygen consumers.

Histone deacetylase inhibitors de-repress tyrosine hydroxylase expression in the olfactory bulb and rostral migratory stream.

Most olfactory bulb (OB) interneurons are derived from neural stem cells in the subventricular zone (SVZ) and migrate to the OB via the rostral migratory stream (RMS). Mature dopaminergic interneurons in the OB glomerular layer are readily identified by their synaptic activity-dependent expression of tyrosine hydroxylase (TH). Paradoxically, TH is not expressed in neural progenitors migrating in the RMS, even though ambient GABA and glutamate depolarize these progenitors. In forebrain slice cultures prepared from transgenic mice containing a GFP reporter gene under the control of the Th 9kb upstream regulatory region, treatment with histone deacetylase (HDAC) inhibitors (either sodium butyrate, Trichostatin A or Scriptaid) induced Th-GFP expression specifically in the RMS independently of depolarizing conditions in the culture media. Th-GFP expression in the glomerular layer was also increased in slices treated with Trichostatin A, but this increased expression was dependent on depolarizing concentrations of KCl in the culture media. Th-GFP expression was also induced in the RMS in vivo by intra-peritoneal injections with either sodium butyrate or valproic acid. Quantitative RT-PCR analysis of neurosphere cultures confirmed that HDAC inhibitors de-repressed Th expression in SVZ-derived neural progenitors. Together, these findings suggest that HDAC function is critical for regulating Th expression levels in both neural progenitors and mature OB dopaminergic neurons. However, the differential responses to the combinatorial exposure of HDAC inhibitors and depolarizing culture conditions indicate that Th expression in mature OB neurons and neural progenitors in the RMS are regulated by distinct HDAC-mediated mechanisms.

Manipulating Adult Neural Stem and Progenitor Cells with G-Quadruplex Ligands.

G-quadruplexes are pervasive nucleic acid secondary structures in mammalian genomes and transcriptomes that regulate gene expression and genome duplication. Small molecule ligands that modify the stability of G-quadruplexes are widely studied in cancer, but whether G-quadruplex ligands can also be used to manipulate cell function under normal development and homeostatic conditions is largely unexplored. Here we show that two related G-quadruplex ligands (pyridostatin and carboxypyridostatin) can reduce proliferation of adult neural stem cell and progenitor cells derived from the adult mouse subventricular zone both in vitro and in vivo. Studies with neurosphere cultures show that pyridostatin reduces proliferation by a mechanism associated with DNA damage and cell death. By contrast, selectively targeting RNA G-quadruplex stability with carboxypyridostatin diminishes proliferation through a mechanism that promotes cell cycle exit and the production of oligodendrocyte progenitors. The ability to generate oligodendrocyte progenitors by targeting RNA G-quadruplex stability, however, is dependent on the cellular environment. Together, these findings show that ligands that can selectively stabilize RNA G-quadruplexes are an important, new class of molecular tool for neural stem and progenitor cell engineering, whereas ligands that target DNA G-quadruplexes have limited utility due to their toxicity.

Zeb2 Is a Regulator of Astrogliosis and Functional Recovery after CNS Injury.

The astrocytic response to injury is characterized on the cellular level, but our understanding of the molecular mechanisms controlling the cellular processes is incomplete. The astrocytic response to injury is similar to wound-healing responses in non-neural tissues that involve epithelial-to-mesenchymal transitions (EMTs) and upregulation in ZEB transcription factors. Here we show that injury-induced astrogliosis increases EMT-related genes expression, including Zeb2, and long non-coding RNAs, including Zeb2os, which facilitates ZEB2 protein translation. In mouse models of either contusive spinal cord injury or transient ischemic stroke, the conditional knockout of Zeb2 in astrocytes attenuates astrogliosis, generates larger lesions, and delays the recovery of motor function. These findings reveal ZEB2 as an important regulator of the astrocytic response to injury and suggest that astrogliosis is an EMT-like process, which provides a conceptual connection for the molecular and cellular similarities between astrogliosis and wound-healing responses in non-neural tissue.

gamma-Aminobutyric acid-mediated regulation of the activity-dependent olfactory bulb dopaminergic phenotype.

gamma-Aminobutyric acid (GABA) regulates the proliferation and migration of olfactory bulb (OB) interneuron progenitors derived from the subventricular zone (SVZ), but the role of GABA in the differentiation of these progenitors has been largely unexplored. This study examines the role of GABA in the differentiation of OB dopaminergic interneurons using neonatal forebrain organotypic slice cultures prepared from transgenic mice expressing green fluorescent protein (GFP) under the control of the tyrosine hydroxylase (Th) gene promoter (ThGFP). KCl-mediated depolarization of the slices induced ThGFP expression. The addition of GABA to the depolarized slices further increased GFP fluorescence by inducing ThGFP expression in an additional set of periglomerular cells. These findings show that GABA promoted differentiation of SVZ-derived OB dopaminergic interneurons and suggest that GABA indirectly regulated Th expression and OB dopaminergic neuron differentiation through an acceleration of the maturation rate for the dopaminergic progenitors. Additional studies revealed that the effect of GABA on ThGFP expression required activation of L- and P/Q-type Ca2+ channels as well as GABA(A) and GABA(B) receptors. These voltage-gated Ca2+ channels and GABA receptors have previously been shown to be required for the coexpressed GABAergic phenotype in the OB interneurons. Together, these findings suggest that Th expression and the differentiation of OB dopaminergic interneurons are coupled to the coexpressed GABAergic phenotype and demonstrate a novel role for GABA in neurogenesis.

Dopamine systems in the forebrain.

The brain contains a number of distinct regions that share expression ofdopamine (DA) and its requisite biosynthetic machinery, but otherwise encompass a diverse array of features and functions. Across the vertebrate family, the olfactory bulb (OB) contains the major DA system in the forebrain. OB DA cells are primarily periglomerular interneurons that define the glomerular structures in which they receive innervation from olfactory receptor neurons as well as mitral and tufted cells, the primary OB output neurons. The OB DA cells are necessary for both discrimination and the dynamic range over which odorant sensory information can be detected. In the embryo, OB DA neurons are derived from the ventricular area of the evaginating telencephalon, the dorsal lateral ganglionic eminence and the septum. However, most OB DA interneurons are generated postnatally and continue to be produced throughout adult life from neural stem cells in the subventricular zone of the lateral ventricle and rostral migratory stream. Adult born OB DA neurons are capable of integrating into existing circuits and do not appear to degenerate in Parkinson's disease. Several genes have been identified that regulate the differentiation of OB DA interneurons from neural stem cells. These include transcription factors that modify the expression of tyrosine hydroxylase, the first enzyme in the DA biosynthetic pathway and a reliable marker of the DA phenotype. Elucidation of the molecular genetic pathways of OB DA differentiation may advance the development of strategies to treat neurological disease.

Progress in the development of olfactory-based bioelectronic chemosensors.

Artificial chemosensory devices have a wide range of applications in industry, security, and medicine. The development of these devices has been inspired by the speed, sensitivity, and selectivity by which the olfactory system in animals can probe the chemical nature of the environment. In this review, we examine how molecular and cellular components of natural olfactory systems have been incorporated into artificial chemosensors, or bioelectronic sensors. We focus on the biological material that has been combined with signal transduction systems to develop artificial chemosensory devices. The strengths and limitations of different biological chemosensory material at the heart of these devices, as well as the reported overall effectiveness of the different bioelectronic sensor designs, is examined. This review also discusses future directions and challenges for continuing to advance development of bioelectronic sensors.

A DNA transcription code for cell-specific gene activation by notch signaling.

BACKGROUND: Cell-specific gene regulation is often controlled by specific combinations of DNA binding sites in target enhancers or promoters. A key question is whether these sites are randomly arranged or if there is an organizational pattern or "architecture" within such regulatory modules. During Notch signaling in Drosophila proneural clusters, cell-specific activation of certain Notch target genes is known to require transcriptional synergy between the Notch intracellular domain (NICD) complexed with CSL proteins bound to "S" DNA sites and proneural bHLH activator proteins bound to nearby "A" DNA sites. Previous studies have implied that arbitrary combinations of S and A DNA binding sites (an "S+A" transcription code) can mediate the Notch-proneural transcriptional synergy. RESULTS: By contrast, we show that the Notch-proneural transcriptional synergy critically requires a particular DNA site architecture ("SPS"), which consists of a pair of specifically-oriented S binding sites. Native and synthetic promoter analysis shows that the SPS architecture in combination with proneural A sites creates a minimal DNA regulatory code, "SPS+A", that is both sufficient and critical for mediating the Notch-proneural synergy. Transgenic Drosophila analysis confirms the SPS orientation requirement during Notch signaling in proneural clusters. We also present evidence that CSL interacts directly with the proneural Daughterless protein, thus providing a molecular mechanism for this synergy. CONCLUSIONS: The SPS architecture functions to mediate or enable the Notch-proneural transcriptional synergy which drives Notch target gene activation in specific cells. Thus, SPS+A is an architectural DNA transcription code that programs a cell-specific pattern of gene expression.

Promoter-specific co-activation by Drosophila mastermind.

Mastermind (Mam) is a co-activator protein of binary complexes consisting of Suppressor of Hairless (Su(H)) and Notch Intracellular Domain (NICD) proteins assembled on cis-regulatory regions of target genes activated by Notch signaling. Current evidence indicates that Mastermind is necessary and sufficient for the formation of a functional Su(H)/NICD/Mam ternary complex on at least one specific architecture of Su(H) binding sites, called the SPS element (Su(H) Paired Sites). However, using transcription assays with a combination of native and synthetic Notch target gene promoters in Drosophila cultured cells, we show here that co-activation of Su(H)/NICD complexes on SPS elements by Mam is promoter-specific. Our novel results suggest this promoter specificity is mediated by additional unknown cis-regulatory elements present in the native promoters that are required for the recruitment of Mam and formation of functional Su(H)/NICD/Mam complexes on SPS elements. Together, the findings in this study suggest Mam is not always necessary and sufficient for co-activation of binary Su(H)/NICD complexes on SPS elements.

Conserved Upstream Regulatory Regions in Mammalian Tyrosine Hydroxylase.

Tyrosine hydroxylase (Th) encodes the rate-limiting enzyme in catecholamine biosynthesis, and the regulation of its transcription is critical for the specification and maintenance of catecholaminergic neuron phenotypes. For many genes, regulatory genomic DNA sequences that are upstream of the proximal promoter control expression levels as well as region-specific expression patterns. The regulatory architecture of the genomic DNA upstream of the Th proximal promoter, however, is poorly understood. In this study, we examined the 11 kb upstream nucleotide sequence of Th from nine mammalian species and identified five highly conserved regions. Using cultured human cells and mouse olfactory bulb tissue, chromatin immunoprecipitation (ChIP) assays show that these conserved regions recruit transcription factors that are established regulators of Th transcription (such as NURR1, PITX3, FOXA2, MEIS2, and PAX6). This analysis also identified a conserved binding site for CTCF, and functional studies in cultured human cells and ChIP assays with mouse tissue show that CTCF is a novel regulator of Th transcription in the forebrain. Together, the findings in this study provide key insights into the upstream regulatory genomic architecture and regulatory mechanisms controlling mammalian Th gene transcription.

BDNF activates an NFI-dependent neurodevelopmental timing program by sequestering NFATc4.

We show that BDNF regulates the timing of neurodevelopment via a novel mechanism of extranuclear sequestration of NFATc4 in Golgi. This leads to accelerated derepression of an NFI temporal occupancy gene program in cerebellar granule cells that includes Bdnf itself, revealing an autoregulatory loop within the program driven by BDNF and NFATc4.