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The epigenetic mechanisms that enable specialized astrocytes to retain neurogenic competence throughout adult life are still poorly understood. Here we show that astrocytes that serve as neural stem cells (NSCs) in the adult mouse subventricular zone (SVZ)

The activity-regulated cytoskeletal protein Arc (also known as Arg3.1) is required for long-term memory formation and synaptic plasticity. Arc expression is robustly induced by activity, and Arc protein localizes to both active synapses and the nucleus. Wh

Multiplexed fluorescence imaging is typically limited to three- to five-plex on standard setups. Sequential imaging methods based on iterative labeling and imaging enable practical higher multiplexing, but generally require a complex fluidic setup with several rounds of slow buffer exchange (tens of minutes to an hour for each exchange step). We report the thermal-plex method, which removes complex and slow buffer exchange steps and provides fluidic-free, rapid sequential imaging. Thermal-plex uses simple DNA probes that are engineered to fluoresce sequentially when, and only when, activated with transient exposure to heating spikes at designated temperatures (thermal channels). Channel switching is fast (<30 s) and is achieved with a commercially available and affordable on-scope heating device. We demonstrate 15-plex RNA imaging (five thermal × three fluorescence channels) in fixed cells and retina tissues in less than 4 min, without using buffer exchange or fluidics. Thermal-plex introduces a new labeling method for efficient sequential multiplexed imaging., (© 2023. The Author(s).)

The cerebral cortex is a cellularly complex structure comprising a rich diversity of neuronal and glial cell types. Cortical neurons can be broadly categorized into two classes-excitatory neurons that use the neurotransmitter glutamate, and inhibitory interneurons that use γ-aminobutyric acid (GABA). Previous developmental studies in rodents have led to a prevailing model in which excitatory neurons are born from progenitors located in the cortex, whereas cortical interneurons are born from a separate population of progenitors located outside the developing cortex in the ganglionic eminences 1-5 . However, the developmental potential of human cortical progenitors has not been thoroughly explored. Here we show that, in addition to excitatory neurons and glia, human cortical progenitors are also capable of producing GABAergic neurons with the transcriptional characteristics and morphologies of cortical interneurons. By developing a cellular barcoding tool called 'single-cell-RNA-sequencing-compatible tracer for identifying clonal relationships' (STICR), we were able to carry out clonal lineage tracing of 1,912 primary human cortical progenitors from six specimens, and to capture both the transcriptional identities and the clonal relationships of their progeny. A subpopulation of cortically born GABAergic neurons was transcriptionally similar to cortical interneurons born from the caudal ganglionic eminence, and these cells were frequently related to excitatory neurons and glia. Our results show that individual human cortical progenitors can generate both excitatory neurons and cortical interneurons, providing a new framework for understanding the origins of neuronal diversity in the human cortex., (© 2021. The Author(s), under exclusive licence to Springer Nature Limited.)

During neurogenesis, mitotic progenitor cells lining the ventricles of the embryonic mouse brain undergo their final rounds of cell division, giving rise to a wide spectrum of postmitotic neurons and glia 1,2 . The link between developmental lineage and cell-type diversity remains an open question. Here we used massively parallel tagging of progenitors to track clonal relationships and transcriptomic signatures during mouse forebrain development. We quantified clonal divergence and convergence across all major cell classes postnatally, and found diverse types of GABAergic neuron that share a common lineage. Divergence of GABAergic clones occurred during embryogenesis upon cell-cycle exit, suggesting that differentiation into subtypes is initiated as a lineage-dependent process at the progenitor cell level., (© 2021. The Author(s).)

Nuclear compartments are thought to play a role in three-dimensional genome organization and gene expression. In mammalian brain, the architecture and dynamics of nuclear compartment-associated genome organization is not known. In this study, we developed Genome Organization using CUT and RUN Technology (GO-CaRT) to map genomic interactions with two nuclear compartments-the nuclear lamina and nuclear speckles-from different regions of the developing mouse, macaque and human brain. Lamina-associated domain (LAD) architecture in cells in vivo is distinct from that of cultured cells, including major differences in LADs previously considered to be cell type invariant. In the mouse and human forebrain, dorsal and ventral neural precursor cells have differences in LAD architecture that correspond to their regional identity. LADs in the human and mouse cortex contain transcriptionally highly active sub-domains characterized by broad depletion of histone-3-lysine-9 dimethylation. Evolutionarily conserved LADs in human, macaque and mouse brain are enriched for transcriptionally active neural genes associated with synapse function. By integrating GO-CaRT maps with genome-wide association study data, we found speckle-associated domains to be enriched for schizophrenia risk loci, indicating a physical relationship between these disease-associated genetic variants and a specific nuclear structure. Our work provides a framework for understanding the relationship between distinct nuclear compartments and genome function in brain development and disease., (© 2021. This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.)

Neural stem cells (NSCs) in the developing and postnatal brain have distinct positional identities that dictate the types of neurons they generate. Although morphogens initially establish NSC positional identity in the neural tube, it is unclear how such regional differences are maintained as the forebrain grows much larger and more anatomically complex. We found that the maintenance of NSC positional identity in the murine brain requires a mixed-lineage leukemia 1 ( Mll1 )-dependent epigenetic memory system. After establishment by sonic hedgehog, ventral NSC identity became independent of this morphogen. Even transient MLL1 inhibition caused a durable loss of ventral identity, resulting in the generation of neurons with the characteristics of dorsal NSCs in vivo. Thus, spatial information provided by morphogens can be transitioned to epigenetic mechanisms that maintain regionally distinct developmental programs in the forebrain., (Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

While it is now appreciated that certain long noncoding RNAs (lncRNAs) have important functions in cell biology, relatively few have been shown to regulate development in vivo, particularly with genetic strategies that establish cis versus trans mechanisms. Pnky is a nuclear-enriched lncRNA that is transcribed divergently from the neighboring proneural transcription factor Pou3f2. Here, we show that conditional deletion of Pnky from the developing cortex regulates the production of projection neurons from neural stem cells (NSCs) in a cell-autonomous manner, altering postnatal cortical lamination. Surprisingly, Pou3f2 expression is not disrupted by deletion of the entire Pnky gene. Moreover, expression of Pnky from a BAC transgene rescues the differential gene expression and increased neurogenesis of Pnky-knockout NSCs, as well as the developmental phenotypes of Pnky-deletion in vivo. Thus, despite being transcribed divergently from a key developmental transcription factor, the lncRNA Pnky regulates development in trans., (Published by Elsevier Inc.)

Throughout embryonic development and into postnatal life, regionally distinct populations of neural progenitor cells (NPCs) collectively generate the many different types of neurons that underlie the complex structure and function of the adult mammalian brain. At very early stages of telencephalic development, NPCs become organized into regional domains that each produce different subsets of neurons. This positional identity of NPCs relates to the regional expression of specific, fate-determining homeodomain transcription factors. As development progresses, the brain undergoes vast changes in both size and shape, yet important aspects of NPC positional identity persist even into the postnatal brain. How can NPC positional identity, which is established so early in brain development, endure the many dynamic, large-scale and complex changes that occur over a relatively long period of time? In this Perspective article, we review data and concepts derived from studies in Drosophila regarding the function of homeobox (Hox) genes, Polycomb group (PcG) and trithorax group (trxG) chromatin regulators. We then discuss how this knowledge may contribute to our understanding of the maintenance of positional identity of NPCs in the mammalian telencephalon. Similar to the axial body plan of Drosophila larvae, there is a segmental nature to NPC positional identity, with loss of specific homeodomain transcription factors causing homeotic-like shifts in brain development. Finally, we speculate about the role of mammalian PcG and trxG factors in the long-term maintenance of NPC positional identity and certain neurodevelopmental disorders.

Neural stem cells (NSCs) are distributed throughout the ventricular-subventricular zone (V-SVZ) in the adult mouse brain. NSCs located in spatially distinct regions of the V-SVZ generate different types of olfactory bulb (OB) neurons, and the regional expression of specific transcription factors correlates with these differences in NSC developmental potential. In a recent article, we show that Nkx2.1-expressing embryonic precursors give rise to NKX2.1+ NSCs located in the ventral V-SVZ of adult mice. Here we characterize a V-SVZ monolayer culture system that retains regional gene expression and neurogenic potential of NSCs from the dorsal and ventral V-SVZ. In particular, we find that Nkx2.1-lineage V-SVZ NSCs maintain Nkx2.1 expression through serial passage and can generate new neurons in vitro. Thus, V-SVZ NSCs retain key aspects of their in vivo regional identity in culture, providing new experimental opportunities for understanding how such developmental patterns are established and maintained during development.

The adult ventricular-subventricular zone (V-SVZ) of the lateral ventricle produces several subtypes of olfactory bulb (OB) interneurons throughout life. Neural stem cells (NSCs) within this zone are heterogeneous, with NSCs located in different regions of the lateral ventricle wall generating distinct OB interneuron subtypes. The regional expression of specific transcription factors appears to correspond to such geographical differences in the developmental potential of V-SVZ NSCs. However, the transcriptional definition and developmental origin of V-SVZ NSC regional identity are not well understood. In this study, we found that a population of NSCs in the ventral region of the V-SVZ expresses the transcription factor Nkx2.1 and is derived from Nkx2.1-expressing (Nkx2.1+) embryonic precursors. To follow the fate of Nkx2.1+ cells and their progeny in vivo, we used mice with an Nkx2.1-CreER "knock-in" allele. Nkx2.1+ V-SVZ NSCs labeled in adult mice generated interneurons for the deep granule cell layer of the OB. Embryonic brain Nkx2.1+ precursors labeled at embryonic day 12.5 gave rise to Nkx2.1+ NSCs of the ventral V-SVZ in postnatal and adult mice. Thus, embryonic Nkx2.1+ neural precursors give rise to a population of Nkx2.1+ NSCs in the ventral V-SVZ where they contribute to the regional heterogeneity of V-SVZ NSCs., (Published by Elsevier Inc.)

Purpose: To compare maximal inspiratory and expiratory pressures (PImax and PEmax, respectively) obtained in Brazilian children who are healthy with reference and predicted values from previous studies., Methods: Respiratory muscle strength of 144 children (63 boys), aged 7 to 11 years, was assessed. A digital manovacuometer was used to measure PImax and PEmax from residual volume and total lung capacity, respectively. Children were assessed in the sitting position while wearing a nose clip., Results: Mean values of PImax for boys and girls were 81.6 ± 20.2 and 66.1 ± 19.5 cmH2O, respectively. Mean values of PEmax in boys and girls were 95.6 ± 21.1 and 78.9 ± 19.7 cmH2O, respectively., Conclusions: Published reference values demonstrated a wide diversity across age groups studied, and published equations were not successful in predicting maximal respiratory pressures; thus, the assessment of respiratory muscle strength of children should consider the minimization of ethnic and methodological differences.

The Consensus on restless legs syndrome is an effort of neurologists from several Brazilian states, which tirelessly reviewed the literature of recent years in search of evidence, both in regard to diagnosis and treatment, according to the Oxford Centre for Evidence-based Medicine.

Commonly, a single aphid species exhibits a wide range of reproductive strategies including cyclical parthenogenesis and obligate parthenogenesis. Sex determination in aphids is chromosomal; females have two X chromosomes, while males have one. X chromosome elimination at male production is generally random, resulting in equal representation of both X chromosomes in sons. However, two studies have demonstrated deviations from randomness in some lineages. One hypothesis to account for such deviations is that recessive deleterious mutations accumulate during bouts of asexual reproduction and affect male viability, resulting in overrepresentation of males with the least deleterious of the two maternal X chromosomes. This hypothesis results in a testable prediction: X chromosome transmission bias will increase with time spent in the asexual phase and should therefore be most extreme in the least sexual aphid life cycle class. Here we test this prediction in Myzus persicae. We used multiple heterozygous X-linked microsatellite markers to screen 1085 males from 95 lines of known life cycle. We found significant deviations from equal representation of X chromosomes in 15 lines; however, these lines included representatives of all life cycles. Our results are inconsistent with the hypothesis that deviations from randomness are attributable to mutation accumulation.

The epigenetic mechanisms that enable specialized astrocytes to retain neurogenic competence throughout adult life are still poorly understood. Here we show that astrocytes that serve as neural stem cells (NSCs) in the adult mouse subventricular zone (SVZ) express the histone methyltransferase EZH2. This Polycomb repressive factor is required for neurogenesis independent of its role in SVZ NSC proliferation, as Ink4a/Arf-deficiency in Ezh2-deleted SVZ NSCs rescues cell proliferation, but neurogenesis remains defective. Olig2 is a direct target of EZH2, and repression of this bHLH transcription factor is critical for neuronal differentiation. Furthermore, Ezh2 prevents the inappropriate activation of genes associated with non-SVZ neuronal subtypes. In the human brain, SVZ cells including local astroglia also express EZH2, correlating with postnatal neurogenesis. Thus, EZH2 is an epigenetic regulator that distinguishes neurogenic SVZ astrocytes, orchestrating distinct and separable aspects of adult stem cell biology, which has important implications for regenerative medicine and oncogenesis.DOI: http://dx.doi.org/10.7554/eLife.02439.001.

The activity-regulated cytoskeletal protein Arc (also known as Arg3.1) is required for long-term memory formation and synaptic plasticity. Arc expression is robustly induced by activity, and Arc protein localizes to both active synapses and the nucleus. Whereas its synaptic function has been examined, it is not clear why or how Arc is localized to the nucleus. We found that murine Arc nuclear expression is regulated by synaptic activity in vivo and in vitro. We identified distinct regions of Arc that control its localization, including a nuclear localization signal, a nuclear retention domain and a nuclear export signal. Arc localization to the nucleus promotes an activity-induced increase in the expression of promyelocytic leukemia nuclear bodies, which decreases GluA1 (also called Gria1) transcription and synaptic strength. We further show that Arc nuclear localization regulates homeostatic plasticity. Thus, Arc mediates the homeostatic response to increased activity by translocating to the nucleus, increasing promyelocytic leukemia protein expression and decreasing GluA1 transcription, ultimately downscaling synaptic strength.

Long noncoding RNAs (lncRNAs) have been described in cell lines and various whole tissues, but lncRNA analysis of development in vivo is limited. Here, we comprehensively analyze lncRNA expression for the adult mouse subventricular zone neural stem cell lineage. We utilize complementary genome-wide techniques including RNA-seq, RNA CaptureSeq, and ChIP-seq to associate specific lncRNAs with neural cell types, developmental processes, and human disease states. By integrating data from chromatin state maps, custom microarrays, and FACS purification of the subventricular zone lineage, we stringently identify lncRNAs with potential roles in adult neurogenesis. shRNA-mediated knockdown of two such lncRNAs, Six3os and Dlx1as, indicate roles for lncRNAs in the glial-neuronal lineage specification of multipotent adult stem cells. Our data and workflow thus provide a uniquely coherent in vivo lncRNA analysis and form the foundation of a user-friendly online resource for the study of lncRNAs in development and disease., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Purpose: The primary concern of this study is to evaluate the clinical course of restless legs syndrome (RLS) in a group of patients who refused treatment., Method: This study compares the outcome of a group of RLS patients after one year without any specific treatment. The International Restless Legs Syndrome Scale (IRLS) was applied at baseline (irls&#95;1) and after one year (irls&#95;2). The patients answered a simple questionnaire for the evaluation of possible environmental or life habit changes after one-year evolution. Serum ferritin was determined at baseline. An improvement index (%improvement) was established through the formula: irls&#95;1- irls&#95;2/irls&#95;1 x 100. Results were compared and a correlation analysis performed., Results: A negative significant correlation was found between the patients' age and irls&#95;2 (r= -0.9 p=0.0018) and between %improvement and irls&#95;2 (r= -0.88 p=0.0039). A positive and significant correlation was determined between %improvement and age. There was only a marginally significant correlation between serum ferritin and ilrs&#95;2 (r= -0.7 p=0.052). No significant changes were found in the other elements analyzed., Conclusion: A favorable outcome was found in this group of RLS patients after one year evolution without treatment. The outcome was positively influenced by the patients' age.

Background & Purpose: The association of obstructive sleep apnea syndrome (OSAS) and restless legs syndrome (RLS) has been reported in the literature for many years. Both conditions may be responsible for fatigue and somnolence complaints secondary to nocturnal sleep disruption. The primary concern of this study is to evaluate the outcome of fatigue and daytime sleepiness symptoms at baseline and after continuous positive air pressure (CPAP) treatment in OSAS patients with and without RLS., Method: A prospective and comparative study between a group of 13 patients with OSAS and a group of 17 patients with OSAS+RLS. Laboratory blood tests and polysomnography were performed at baseline. The Epworth Sleepiness Scale (ESS) and the Pichots questionnaire of fatigue/depression (PIC) were applied before and after 3 months of CPAP treatment. Results were compared., Results: No significant differences were found on PSG and laboratory results at baseline. Both groups had similar ESS and PIC scores at baseline (p=0.73 and 0.08, respectively). After n-CPAP, OSAS+RLS patients showed higher ESS and PIC scores (p=0.017 and 0.03, respectively)., Conclusions: Despite a favorable general response, n-CPAP seemed less effective in treating fatigue and sleepiness in the OSAS+RLS group.

Objective: To compare MSLT parameters in two groups of patients with daytime sleepiness, correlated to the occurrence and onset of dreams., Method: Patients were submitted to the MSLT between January/1999 and June/2002. Sleep onset latency, REM sleep latency and total sleep time were determined. The occurrence of dreams was inquired following each MSLT series. Patients were classified as narcoleptic (N) or non-narcoleptic (NN)., Results: Thirty patients were studied, 12 were classified as narcoleptics (N group; 40%), while the remaining 18 as non-narcoleptic (NN group; 60%). Thirty MSLT were performed, resulting in 146 series. Sleep was detected in 126 series (86%) and dreams in 56 series (44.44%). Mean sleep time in the N group was 16.0+/-6.3 min, while 10.5+/-7.5 min in the NN group (p<0.0001). Mean sleep latency was 2.0+/-2.2 min and 7.2+/-6.0 min in the N and NN group, respectively (p<0.001). Mean REM sleep latency in the N group was 3.2+/-3.1min and 6.9+/-3.7 min in the NN group (p=0.021). Dreams occurred in 56.9% of the N group series and 28.4% in that of the NN group (p=0.0009). Dream frequency was detected in 29.8% and 75% of the NREM series of the N and NN groups, respectively (p=0.0001)., Conclusion: Patients from the N group, compared to the NN group, slept longer and earlier, demonstrated a shorter REM sleep onset and greater dream frequency. NN patients had a greater dream frequency in NREM series. Thus, the occurrence of dreams during NREM in the MSLT may contribute to differentially diagnose narcolepsy and daytime sleepiness.