RESUMEN

Proneural transcription factors establish molecular cascades to orchestrate neuronal diversity. One such transcription factor, Atonal homolog 1 (Atoh1), gives rise to cerebellar excitatory neurons and over 30 distinct nuclei in the brainstem critical for hearing, breathing, and balance. Although Atoh1 lineage neurons have been qualitatively described, the transcriptional programs that drive their fate decisions and the full extent of their diversity remain unknown. Here, we analyzed single-cell RNA sequencing and ATOH1 DNA binding in Atoh1 lineage neurons of the developing mouse hindbrain. This high-resolution dataset identified markers for specific brainstem nuclei and demonstrated that transcriptionally heterogeneous progenitors require ATOH1 for proper migration. Moreover, we identified a sizable population of proliferating unipolar brush cell progenitors in the mouse Atoh1 lineage, previously described in humans as the origin of one medulloblastoma subtype. Collectively, our data provide insights into the developing mouse hindbrain and markers for functional assessment of understudied neuronal populations.

Asunto(s)

Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico , Linaje de la Célula , Neuronas , Rombencéfalo , Análisis de la Célula Individual , Transcriptoma , Animales , Rombencéfalo/metabolismo , Rombencéfalo/citología , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Ratones , Neuronas/metabolismo , Neuronas/citología , Linaje de la Célula/genética , Análisis de la Célula Individual/métodos , Transcriptoma/genética , Diferenciación Celular , Regulación del Desarrollo de la Expresión Génica , Neurogénesis/genética , Movimiento Celular

RESUMEN

The most successful obesity therapeutics, glucagon-like peptide-1 receptor (GLP1R) agonists, cause aversive responses such as nausea and vomiting1,2, effects that may contribute to their efficacy. Here, we investigated the brain circuits that link satiety to aversion, and unexpectedly discovered that the neural circuits mediating these effects are functionally separable. Systematic investigation across drug-accessible GLP1R populations revealed that only hindbrain neurons are required for the efficacy of GLP1-based obesity drugs. In vivo two-photon imaging of hindbrain GLP1R neurons demonstrated that most neurons are tuned to either nutritive or aversive stimuli, but not both. Furthermore, simultaneous imaging of hindbrain subregions indicated that area postrema (AP) GLP1R neurons are broadly responsive, whereas nucleus of the solitary tract (NTS) GLP1R neurons are biased towards nutritive stimuli. Strikingly, separate manipulation of these populations demonstrated that activation of NTSGLP1R neurons triggers satiety in the absence of aversion, whereas activation of APGLP1R neurons triggers strong aversion with food intake reduction. Anatomical and behavioural analyses revealed that NTSGLP1R and APGLP1R neurons send projections to different downstream brain regions to drive satiety and aversion, respectively. Importantly, GLP1R agonists reduce food intake even when the aversion pathway is inhibited. Overall, these findings highlight NTSGLP1R neurons as a population that could be selectively targeted to promote weight loss while avoiding the adverse side effects that limit treatment adherence.

Asunto(s)

Fármacos Antiobesidad , Reacción de Prevención , Receptor del Péptido 1 Similar al Glucagón , Vías Nerviosas , Rombencéfalo , Respuesta de Saciedad , Animales , Femenino , Masculino , Ratones , Fármacos Antiobesidad/efectos adversos , Fármacos Antiobesidad/farmacología , Área Postrema/metabolismo , Área Postrema/efectos de los fármacos , Reacción de Prevención/efectos de los fármacos , Reacción de Prevención/fisiología , Ingestión de Alimentos/efectos de los fármacos , Ingestión de Alimentos/fisiología , Péptido 1 Similar al Glucagón/metabolismo , Receptor del Péptido 1 Similar al Glucagón/agonistas , Receptor del Péptido 1 Similar al Glucagón/metabolismo , Ratones Endogámicos C57BL , Vías Nerviosas/efectos de los fármacos , Neuronas/metabolismo , Neuronas/fisiología , Neuronas/efectos de los fármacos , Obesidad/metabolismo , Rombencéfalo/citología , Rombencéfalo/efectos de los fármacos , Rombencéfalo/metabolismo , Rombencéfalo/fisiología , Respuesta de Saciedad/efectos de los fármacos , Respuesta de Saciedad/fisiología , Núcleo Solitario/citología , Núcleo Solitario/efectos de los fármacos , Núcleo Solitario/metabolismo , Núcleo Solitario/fisiología , Alimentos

RESUMEN

It has been reported that the clinical symptoms of functional dyspepsia (FD) exacerbate upon stress while the gender-related factors have been incompletely understood. This study aims to investigate the role of sex in chronic heterotypic stress (CHS)-induced autonomic and gastric motor dysfunction. For CHS, the rats were exposed to the combination of different stressors for 7 consecutive days. Subsequently, electrocardiography was recorded in anesthetized rats to evaluate heart rate variability (HRV) for the determination of autonomic outflow and sympathovagal balance. Solid gastric emptying (GE) was measured in control and CHS-loaded male and female rats. The immunoreactivities of catecholaminergic cell marker tyrosine hydroxylase (TH), choline acetyltransferase (ChAT), corticotropin releasing factor (CRF), and estrogen receptor (ER-α/ß) were evaluated in medullary and pontine brainstem sections by immunohistochemistry. Compared with the controls, CHS significantly delayed GE in males but not in females. There was no significant sex-related difference in parasympathetic indicator HF under either control or CHS conditions. Sympathetic indicator LF was significantly higher in control females compared to the males. The higher sympathetic output in females was found to be attenuated upon CHS; in contrast, the elevated sympathetic output was detected in CHS-loaded males. No sex- or stress-related effect was observed on ChAT immunoreactivity in the dorsal motor nucleus of N.vagus (DMV). In males, greater number of TH-ir cells was observed in the caudal locus coeruleus (LC), while they were more densely detected in the rostral LC of females. Regardless of sex, CHS elevated immunoreactivity of TH throughout the LC. Under basal conditions, greater number of TH-ir cells was detected in the rostral ventrolateral medulla (RVLM) of females. In contrast, CHS remarkably increased the number of TH-ir cells in the RVLM of males which was found to be decreased in females. There was no sex-related alteration in TH immunoreactivity in the nucleus tractus solitarius (NTS) of control rats, while CHS affected both sexes in a similar manner. Compared with females, CRF immunoreactivity was prominently observed in control males, while both of which were stimulated by CHS. ER-α/ß was found to be co-expressed with TH in the NTS and LC which exhibit no alteration related to either sex or stress status. These results indicate a sexual dimorphism in the catecholaminergic and the CRF system in brainstem which might be involved in the CHS-induced autonomic and visceral dysfunction occurred in males.

Asunto(s)

Ratas Sprague-Dawley , Caracteres Sexuales , Estrés Psicológico , Animales , Masculino , Femenino , Estrés Psicológico/metabolismo , Estrés Psicológico/fisiopatología , Ratas , Rombencéfalo/metabolismo , Motilidad Gastrointestinal/fisiología , Catecolaminas/metabolismo , Tirosina 3-Monooxigenasa/metabolismo , Sistema Nervioso Autónomo/fisiopatología , Sistema Nervioso Autónomo/metabolismo , Frecuencia Cardíaca/fisiología , Hormona Liberadora de Corticotropina/metabolismo , Vaciamiento Gástrico/fisiología , Colina O-Acetiltransferasa/metabolismo

RESUMEN

Inherited deficiency of the RNA lariat-debranching enzyme 1 (DBR1) is a rare etiology of brainstem viral encephalitis. The cellular basis of disease and the range of viral predisposition are unclear. We report inherited DBR1 deficiency in a 14-year-old boy who suffered from isolated SARS-CoV-2 brainstem encephalitis. The patient is homozygous for a previously reported hypomorphic and pathogenic DBR1 variant (I120T). Consistently, DBR1 I120T/I120T fibroblasts from affected individuals from this and another unrelated kindred have similarly low levels of DBR1 protein and high levels of RNA lariats. DBR1 I120T/I120T human pluripotent stem cell (hPSC)-derived hindbrain neurons are highly susceptible to SARS-CoV-2 infection. Exogenous WT DBR1 expression in DBR1 I120T/I120T fibroblasts and hindbrain neurons rescued the RNA lariat accumulation phenotype. Moreover, expression of exogenous RNA lariats, mimicking DBR1 deficiency, increased the susceptibility of WT hindbrain neurons to SARS-CoV-2 infection. Inborn errors of DBR1 impair hindbrain neuron-intrinsic antiviral immunity, predisposing to viral infections of the brainstem, including that by SARS-CoV-2.

Asunto(s)

Tronco Encefálico , COVID-19 , Neuronas , SARS-CoV-2 , Humanos , Masculino , SARS-CoV-2/genética , COVID-19/genética , COVID-19/virología , Tronco Encefálico/patología , Tronco Encefálico/virología , Tronco Encefálico/metabolismo , Adolescente , Neuronas/metabolismo , Neuronas/patología , Encefalitis Viral/genética , Encefalitis Viral/patología , Encefalitis Viral/virología , Fibroblastos/metabolismo , Rombencéfalo/metabolismo

RESUMEN

We identify a population of Protogenin-positive (PRTG+ve) MYChigh NESTINlow stem cells in the four-week-old human embryonic hindbrain that subsequently localizes to the ventricular zone of the rhombic lip (RLVZ). Oncogenic transformation of early Prtg+ve rhombic lip stem cells initiates group 3 medulloblastoma (Gr3-MB)-like tumors. PRTG+ve stem cells grow adjacent to a human-specific interposed vascular plexus in the RLVZ, a phenotype that is recapitulated in Gr3-MB but not in other types of medulloblastoma. Co-culture of Gr3-MB with endothelial cells promotes tumor stem cell growth, with the endothelial cells adopting an immature phenotype. Targeting the PRTGhigh compartment of Gr3-MB in vivo using either the diphtheria toxin system or chimeric antigen receptor T cells constitutes effective therapy. Human Gr3-MBs likely arise from early embryonic RLVZ PRTG+ve stem cells inhabiting a specific perivascular niche. Targeting the PRTGhigh compartment and/or the perivascular niche represents an approach to treat children with Gr3-MB.

Asunto(s)

Meduloblastoma , Células Madre Neoplásicas , Humanos , Meduloblastoma/patología , Meduloblastoma/metabolismo , Animales , Células Madre Neoplásicas/metabolismo , Células Madre Neoplásicas/patología , Ratones , Rombencéfalo/metabolismo , Rombencéfalo/embriología , Neoplasias Cerebelosas/metabolismo , Neoplasias Cerebelosas/patología , Células Endoteliales/metabolismo , Nicho de Células Madre , Células Madre/metabolismo , Técnicas de Cocultivo , Estructuras Embrionarias , Metencéfalo/embriología

RESUMEN

Interbacterial competition is known to shape the microbial communities found in the host, however the interplay between this competition and host defense are less clear. Here, we use the zebrafish hindbrain ventricle (HBV) as an in vivo platform to investigate host responses to defined bacterial communities with distinct forms of interbacterial competition. We found that antibacterial activity of the type VI secretion system (T6SS) from both Vibrio cholerae and Acinetobacter baylyi can induce host inflammation and sensitize the host to infection independent of any individual effector. Chemical suppression of inflammation could resolve T6SS-dependent differences in host survival, but the mechanism by which this occurred differed between the two bacterial species. By contrast, colicin-mediated antagonism elicited by an avirulent strain of Shigella sonnei induced a negligible host response despite being a more potent bacterial killer, resulting in no impact on A. baylyi or V. cholerae virulence. Altogether, these results provide insight into how different modes of interbacterial competition in vivo affect the host in distinct ways.

Asunto(s)

Sistemas de Secreción Tipo VI , Vibrio cholerae , Pez Cebra , Animales , Pez Cebra/microbiología , Sistemas de Secreción Tipo VI/metabolismo , Vibrio cholerae/patogenicidad , Acinetobacter , Virulencia , Interacciones Huésped-Patógeno , Antibiosis/fisiología , Rombencéfalo/microbiología , Rombencéfalo/metabolismo

RESUMEN

Mineralocorticoids play a key role in hydromineral balance by regulating sodium retention and potassium wasting. Through favoring sodium, mineralocorticoids can cause hypertension from fluid overload under conditions of hyperaldosteronism, such as aldosterone-secreting tumors. An often-overlooked mechanism by which aldosterone functions to increase sodium is through stimulation of salt appetite. To drive sodium intake, aldosterone targets neurons in the hindbrain which uniquely express 11ß-hydroxysteroid dehydrogenase type 2 (HSD2). This enzyme is a necessary precondition for aldosterone-sensing cells as it metabolizes glucocorticoids - preventing their activation of the mineralocorticoid receptor. In this review, we will consider the role of hindbrain HSD2 neurons in regulating sodium appetite by discussing HSD2 expression in the brain, regulation of hindbrain HSD2 neuron activity, and the circuitry mediating the effects of these aldosterone-sensitive neurons. Reducing the activity of hindbrain HSD2 neurons may be a viable strategy to reduce sodium intake and cardiovascular risk, particularly for conditions of hyperaldosteronism.

Asunto(s)

11-beta-Hidroxiesteroide Deshidrogenasa de Tipo 2 , Aldosterona , Apetito , Neuronas , Rombencéfalo , Rombencéfalo/metabolismo , Animales , Aldosterona/metabolismo , Neuronas/metabolismo , Humanos , 11-beta-Hidroxiesteroide Deshidrogenasa de Tipo 2/metabolismo , Sodio/metabolismo

RESUMEN

Cerebellar granule neuron progenitors (GNPs) originate from the upper rhombic lip (URL), a germinative niche in which developmental defects produce human diseases. T-cell factor (TCF) responsiveness and Notch dependence are hallmarks of self-renewal in neural stem cells. TCF activity, together with transcripts encoding proneural gene repressors hairy and enhancer of split (Hes/Hey), are detected in the URL; however, their functions and regulatory modes are undeciphered. Here, we established amphibian as a pertinent model for studying vertebrate URL development. The amphibian long-lived URL is TCF active, whereas the external granular layer (EGL) is non-proliferative and expresses hes4 and hes5 genes. Using functional and transcriptomic approaches, we show that TCF activity is necessary for URL emergence and maintenance. We establish that the transcription factor Barhl1 controls GNP exit from the URL, acting partly through direct TCF inhibition. Identification of Barhl1 target genes suggests that, besides TCF, Barhl1 inhibits transcription of hes5 genes independently of Notch signaling. Observations in amniotes suggest a conserved role for Barhl in maintenance of the URL and/or EGL via co-regulation of TCF, Hes and Hey genes.

Asunto(s)

Cerebelo , Células-Madre Neurales , Animales , Células-Madre Neurales/metabolismo , Células-Madre Neurales/citología , Cerebelo/citología , Cerebelo/metabolismo , Regulación del Desarrollo de la Expresión Génica , Neuronas/metabolismo , Neuronas/citología , Receptores Notch/metabolismo , Receptores Notch/genética , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Transducción de Señal , Factores de Transcripción/metabolismo , Factores de Transcripción/genética , Rombencéfalo/metabolismo , Rombencéfalo/citología , Nicho de Células Madre , Proteínas del Tejido Nervioso/metabolismo , Proteínas del Tejido Nervioso/genética

RESUMEN

Neurons in the caudal nucleus of the solitary tract (cNTS) and intermediate reticular nucleus (IRt) that express the glucagon gene (Gcg) give rise to glucagon-like peptide 1 (GLP1)-immunopositive axons in the spinal cord and many subcortical brain regions. Central GLP1 receptor signaling contributes to motivated behavior and stress responses in rats and mice, in which hindbrain GLP1 neurons are activated to express c-Fos in a metabolic state-dependent manner. The present study examined whether GLP1 inputs to distinct brain regions arise from distinct subsets of Gcg-expressing neurons, and mapped the distribution of axon collaterals arising from projection-defined GLP1 neural populations. Using our Gcg-Cre knock-in rat model, Cre-dependent adeno-associated virus (AAV) tracing was conducted in adult male and female rats to compare axonal projections of IRt versus cNTS GLP1 neurons. Overlapping projections were observed in all brain regions that receive GLP1 input, with the caveat that cNTS injections produced Cre-dependent labeling of some IRt neurons, and vice versa. In additional experiments, specific diencephalic or limbic forebrain nuclei were microinjected with Cre-dependent retrograde AAVs (AAVrg) that expressed reporters to fully label the axon collaterals of transduced GLP1 neurons. AAVrg injected into each forebrain site labeled Gcg-expressing neurons in both the cNTS and IRt. The collective axon collaterals of labeled neurons entered the spinal cord and every brain region previously reported to contain GLP1-positive axons. These results indicate that the axons of GLP1 neural populations that innervate the thalamic paraventricular nucleus, paraventricular nucleus of the hypothalamus, and/or bed nucleus of the stria terminalis collectively innervate all central regions that receive GLP1 axonal input.

Asunto(s)

Axones , Péptido 1 Similar al Glucagón , Neuronas , Rombencéfalo , Animales , Masculino , Femenino , Ratas , Péptido 1 Similar al Glucagón/metabolismo , Péptido 1 Similar al Glucagón/genética , Neuronas/metabolismo , Axones/metabolismo , Rombencéfalo/metabolismo , Vías Nerviosas/metabolismo , Ratas Sprague-Dawley , Hipotálamo/metabolismo , Hipotálamo/citología , Prosencéfalo/metabolismo , Sistema Límbico/metabolismo , Núcleo Solitario/metabolismo , Receptor del Péptido 1 Similar al Glucagón/genética , Receptor del Péptido 1 Similar al Glucagón/metabolismo

RESUMEN

The nucleus incertus (NI), a conserved hindbrain structure implicated in the stress response, arousal, and memory, is a major site for production of the neuropeptide relaxin-3. On the basis of goosecoid homeobox 2 (gsc2) expression, we identified a neuronal cluster that lies adjacent to relaxin 3a (rln3a) neurons in the zebrafish analogue of the NI. To delineate the characteristics of the gsc2 and rln3a NI neurons, we used CRISPR/Cas9 targeted integration to drive gene expression specifically in each neuronal group, and found that they differ in their efferent and afferent connectivity, spontaneous activity, and functional properties. gsc2 and rln3a NI neurons have widely divergent projection patterns and innervate distinct subregions of the midbrain interpeduncular nucleus (IPN). Whereas gsc2 neurons are activated more robustly by electric shock, rln3a neurons exhibit spontaneous fluctuations in calcium signaling and regulate locomotor activity. Our findings define heterogeneous neurons in the NI and provide new tools to probe its diverse functions.

Asunto(s)

Neuronas , Pez Cebra , Animales , Neuronas/fisiología , Neuronas/metabolismo , Relaxina/metabolismo , Relaxina/genética , Proteínas de Pez Cebra/metabolismo , Proteínas de Pez Cebra/genética , Proteínas de Homeodominio/metabolismo , Proteínas de Homeodominio/genética , Sistemas CRISPR-Cas , Rombencéfalo/fisiología , Rombencéfalo/metabolismo

RESUMEN

The hindbrain, which develops from the anterior end of the neural tube expansion, can differentiate into the metencephalon and myelencephalon, with varying sizes and functions. The midbrain-hindbrain boundary (MHB) and hindbrain myelencephalon/ventral midline (HMVM) are known to be the source of the progenitors for the anterior hindbrain and myelencephalon, respectively. However, the molecular networks regulating hindbrain morphogenesis in these structures remain unclear. In this study, we show that retinoblastoma 1 (rb1) is highly expressed at the MHB and HMVM in zebrafish. Knocking out rb1 in mice and zebrafish results in an enlarged hindbrain due to hindbrain neuronal hyperproliferation. Further study reveals that Rb1 controls the hindbrain morphogenesis by suppressing the expression of Gbx1/Gbx2, essential transcription factors for hindbrain development, through its binding to E2f3/Hdac1, respectively. Interestingly, we find that Gbx1 and Gbx2 are expressed in different types of hindbrain neurons, suggesting distinct roles in hindbrain morphogenesis. In summary, our study clarifies the specific role of RB1 in hindbrain neural cell proliferation and morphogenesis by regulating the E2f3-Gbx1 axis and the Hdac1-Gbx2 axis. These findings provide a research paradigm for exploring the differential proliferation of neurons in various brain regions.

Asunto(s)

Regulación del Desarrollo de la Expresión Génica , Proteínas de Homeodominio , Morfogénesis , Rombencéfalo , Pez Cebra , Animales , Ratones , Proliferación Celular/genética , Regulación del Desarrollo de la Expresión Génica/genética , Proteínas de Homeodominio/genética , Proteínas de Homeodominio/metabolismo , Morfogénesis/genética , Neuronas/metabolismo , Neuronas/citología , Proteína de Retinoblastoma/genética , Proteína de Retinoblastoma/metabolismo , Rombencéfalo/metabolismo , Rombencéfalo/crecimiento & desarrollo , Rombencéfalo/embriología , Pez Cebra/genética , Pez Cebra/metabolismo , Proteínas de Pez Cebra/genética , Proteínas de Pez Cebra/metabolismo

RESUMEN

Retinoic acid (RA) is involved in antero-posterior patterning of the chordate body axis and, in jawed vertebrates, has been shown to play a major role at multiple levels of the gene regulatory network (GRN) regulating hindbrain segmentation. Knowing when and how RA became coupled to the core hindbrain GRN is important for understanding how ancient signaling pathways and patterning genes can evolve and generate diversity. Hence, we investigated the link between RA signaling and hindbrain segmentation in the sea lamprey Petromyzon marinus, an important jawless vertebrate model providing clues to decipher ancestral vertebrate features. Combining genomics, gene expression, and functional analyses of major components involved in RA synthesis (Aldh1as) and degradation (Cyp26s), we demonstrate that RA signaling is coupled to hindbrain segmentation in lamprey. Thus, the link between RA signaling and hindbrain segmentation is a pan vertebrate feature of the hindbrain and likely evolved at the base of vertebrates.

Asunto(s)

Cordados , Petromyzon , Animales , Petromyzon/genética , Tretinoina/metabolismo , Vertebrados/genética , Rombencéfalo/metabolismo , Regulación del Desarrollo de la Expresión Génica

RESUMEN

OBJECTIVE: The central melanocortin system is essential for the regulation of food intake and body weight. Agouti-related protein (AgRP) is the sole orexigenic component of the central melanocortin system and is conserved across mammalian species. AgRP is currently known to be expressed exclusively in the mediobasal hypothalamus, and hypothalamic AgRP-expressing neurons are essential for feeding. Here we characterized a previously unknown population of AgRP cells in the mouse hindbrain. METHODS: Expression of AgRP in the hindbrain was investigated using gene expression analysis, single-cell RNA sequencing, immunofluorescent analysis and multiple transgenic mice with reporter expressions. Activation of AgRP neurons was achieved by Designer Receptors Exclusively Activated by Designer Drugs (DREADD) and by transcranial focal photo-stimulation using a step-function opsin with ultra-high light sensitivity (SOUL). RESULTS: AgRP expressing cells were present in the area postrema (AP) and the adjacent subpostrema area (SubP) and commissural nucleus of the solitary tract (cNTS) of the mouse hindbrain (termed AgRPHind herein). AgRPHind cells consisted of locally projecting neurons as well as tanycyte-like cells. Food deprivation stimulated hindbrain Agrp expression as well as neuronal activity of subsets of AgRPHind cells. In adult mice that lacked hypothalamic AgRP neurons, chemogenetic activation of AgRP neurons resulted in hyperphagia and weight gain. In addition, transcranial focal photo-stimulation of hindbrain AgRP cells increased food intake in adult mice with or without hypothalamic AgRP neurons. CONCLUSIONS: Our study indicates that the central melanocortin system in the hindbrain possesses an orexigenic component, and that AgRPHind neurons stimulate feeding independently of hypothalamic AgRP neurons.

Asunto(s)

Hipotálamo , Melanocortinas , Ratones , Animales , Proteína Relacionada con Agouti/genética , Proteína Relacionada con Agouti/metabolismo , Hipotálamo/metabolismo , Ratones Transgénicos , Melanocortinas/metabolismo , Rombencéfalo/metabolismo , Mamíferos/metabolismo

RESUMEN

The interplay between neural progenitors and stem cells (NPSCs), and their extracellular matrix (ECM) is a crucial regulatory mechanism that determines their behavior. Nonetheless, how the ECM dictates the state of NPSCs remains elusive. The hindbrain is valuable to examine this relationship, as cells in the ventricular surface of hindbrain boundaries (HBs), which arise between any two neighboring rhombomeres, express the NPSC marker Sox2, while being surrounded with the membrane-bound ECM molecule chondroitin sulphate proteoglycan (CSPG), in chick and mouse embryos. CSPG expression was used to isolate HB Sox2+ cells for RNA-sequencing, revealing their distinguished molecular properties as typical NPSCs, which express known and newly identified genes relating to stem cells, cancer, the matrisome and cell cycle. In contrast, the CSPG- non-HB cells, displayed clear neural-differentiation transcriptome. To address whether CSPG is significant for hindbrain development, its expression was manipulated in vivo and in vitro. CSPG manipulations shifted the stem versus differentiation state of HB cells, evident by their behavior and altered gene expression. These results provide further understanding of the uniqueness of hindbrain boundaries as repetitive pools of NPSCs in-between the rapidly growing rhombomeres, which rely on their microenvironment to maintain their undifferentiated state during development.

Asunto(s)

Células-Madre Neurales , Proteoglicanos , Ratones , Animales , Proteoglicanos/metabolismo , Sulfatos de Condroitina , Proteoglicanos Tipo Condroitín Sulfato , Matriz Extracelular/metabolismo , Rombencéfalo/metabolismo , Células-Madre Neurales/metabolismo

RESUMEN

OBJECTIVE: The dorsal vagal complex (DVC) of the hindbrain is a major point of integration for central and peripheral signals that regulate a wide variety of metabolic functions to maintain energy balance. The REV-ERB nuclear receptors are important modulators of molecular metabolism, but their role in the DVC has yet to be established. METHODS: Male REV-ERBα/ß floxed mice received stereotaxic injections of a Cre expressing virus to the DVC to create the DVC REV-ERBα/ß double knockout (DVC RDKO). Control littermates received stereotaxic injections to the DVC of a green fluorescent protein expressing virus. Animals were maintained on a normal chow diet or a 60% high-fat diet to observe the metabolic phenotype arising from DVC RDKO under healthy and metabolically stressed conditions. RESULTS: DVC RDKO animals on high-fat diet exhibited increased weight gain compared to control animals maintained on the same diet. Increased weight gain in DVC RDKO animals was associated with decreased basal metabolic rate and dampened signature of brown adipose tissue activity. RDKO decreased gene expression of calcitonin receptor in the DVC and tyrosine hydroxylase in the brown adipose tissue. CONCLUSIONS: These results suggest a previously unappreciated role of REV-ERB nuclear receptors in the DVC for maintaining energy balance and metabolic rate potentially through indirect sympathetic outflow to the brown adipose tissue.

Asunto(s)

Tejido Adiposo Pardo , Rombencéfalo , Animales , Masculino , Ratones , Tejido Adiposo Pardo/metabolismo , Dieta Alta en Grasa/efectos adversos , Obesidad/metabolismo , Receptores Citoplasmáticos y Nucleares/metabolismo , Rombencéfalo/metabolismo , Aumento de Peso

RESUMEN

The function of the mammalian brain relies upon the specification and spatial positioning of diversely specialized cell types. Yet, the molecular identities of the cell types and their positions within individual anatomical structures remain incompletely known. To construct a comprehensive atlas of cell types in each brain structure, we paired high-throughput single-nucleus RNA sequencing with Slide-seq1,2-a recently developed spatial transcriptomics method with near-cellular resolution-across the entire mouse brain. Integration of these datasets revealed the cell type composition of each neuroanatomical structure. Cell type diversity was found to be remarkably high in the midbrain, hindbrain and hypothalamus, with most clusters requiring a combination of at least three discrete gene expression markers to uniquely define them. Using these data, we developed a framework for genetically accessing each cell type, comprehensively characterized neuropeptide and neurotransmitter signalling, elucidated region-specific specializations in activity-regulated gene expression and ascertained the heritability enrichment of neurological and psychiatric phenotypes. These data, available as an online resource ( www.BrainCellData.org ), should find diverse applications across neuroscience, including the construction of new genetic tools and the prioritization of specific cell types and circuits in the study of brain diseases.

Asunto(s)

Encéfalo , Perfilación de la Expresión Génica , Animales , Ratones , Encéfalo/anatomía & histología , Encéfalo/citología , Encéfalo/metabolismo , Perfilación de la Expresión Génica/métodos , Secuenciación de Nucleótidos de Alto Rendimiento , Hipotálamo/citología , Hipotálamo/metabolismo , Mesencéfalo/citología , Mesencéfalo/metabolismo , Neuropéptidos/metabolismo , Neurotransmisores/metabolismo , Fenotipo , Rombencéfalo/citología , Rombencéfalo/metabolismo , Análisis de Expresión Génica de una Sola Célula , Transcriptoma/genética

Asunto(s)

Células Ependimogliales , Pez Cebra , Animales , Células Ependimogliales/metabolismo , Animales Modificados Genéticamente/metabolismo , Proteínas de Pez Cebra/genética , Proteínas de Pez Cebra/metabolismo , Rombencéfalo/metabolismo , Proliferación Celular/fisiología , Neuroglía/metabolismo

RESUMEN

Hindbrain adrenergic/noradrenergic nuclei facilitate endocrine and autonomic responses to physical and psychological challenges. Neurons that synthesize adrenaline and noradrenaline target hypothalamic structures to modulate endocrine responses while descending spinal projections regulate sympathetic function. Furthermore, these neurons respond to diverse stress-related metabolic, autonomic, and psychosocial challenges. Accordingly, adrenergic and noradrenergic nuclei are integrative hubs that promote physiological adaptation to maintain homeostasis. However, the precise mechanisms through which adrenaline- and noradrenaline-synthesizing neurons sense interoceptive and exteroceptive cues to coordinate physiological responses have yet to be fully elucidated. Additionally, the regulatory role of these cells in the context of chronic stress has received limited attention. This mini-review consolidates reports from preclinical rodent studies on the organization and function of brainstem adrenaline and noradrenaline cells to provide a framework for how these nuclei coordinate endocrine and autonomic physiology. This includes identification of hindbrain adrenaline- and noradrenaline-producing cell groups and their role in stress responding through neurosecretory and autonomic engagement. Although temporally and mechanistically distinct, the endocrine and autonomic stress axes are complementary and interconnected. Therefore, the interplay between brainstem adrenergic/noradrenergic nuclei and peripheral physiological systems is necessary for integrated stress responses and organismal survival.

Asunto(s)

Adrenérgicos , Norepinefrina , Norepinefrina/metabolismo , Epinefrina , Tronco Encefálico/metabolismo , Rombencéfalo/metabolismo

RESUMEN

Genetic variants affecting Heterogeneous Nuclear Ribonucleoprotein U (HNRNPU) have been identified in several neurodevelopmental disorders (NDDs). HNRNPU is widely expressed in the human brain and shows the highest postnatal expression in the cerebellum. Recent studies have investigated the role of HNRNPU in cerebral cortical development, but the effects of HNRNPU deficiency on cerebellar development remain unknown. Here, we describe the molecular and cellular outcomes of HNRNPU locus deficiency during in vitro neural differentiation of patient-derived and isogenic neuroepithelial stem cells with a hindbrain profile. We demonstrate that HNRNPU deficiency leads to chromatin remodeling of A/B compartments, and transcriptional rewiring, partly by impacting exon inclusion during mRNA processing. Genomic regions affected by the chromatin restructuring and host genes of exon usage differences show a strong enrichment for genes implicated in epilepsies, intellectual disability, and autism. Lastly, we show that at the cellular level HNRNPU downregulation leads to an increased fraction of neural progenitors in the maturing neuronal population. We conclude that the HNRNPU locus is involved in delayed commitment of neural progenitors to differentiate in cell types with hindbrain profile.

Asunto(s)

Ribonucleoproteína Heterogénea-Nuclear Grupo U , Trastornos del Neurodesarrollo , Humanos , Cromatina , Ribonucleoproteína Heterogénea-Nuclear Grupo U/genética , Ribonucleoproteína Heterogénea-Nuclear Grupo U/metabolismo , Trastornos del Neurodesarrollo/genética , Neurogénesis/genética , Rombencéfalo/metabolismo

RESUMEN

Advances in tau biology and the difficulties of amyloid-directed immunotherapeutics have heightened interest in tau as a target for small molecule drug discovery for neurodegenerative diseases. Here, we evaluated OLX-07010, a small molecule inhibitor of tau self-association, for the prevention of tau aggregation. The primary endpoint of the study was statistically significant reduction of insoluble tau aggregates in treated JNPL3 mice compared with Vehicle-control mice. Secondary endpoints were dose-dependent reduction of insoluble tau aggregates, reduction of phosphorylated tau, and reduction of soluble tau. This study was performed in JNPL3 mice, which are representative of inherited forms of 4-repeat tauopathies with the P301L tau mutation (e.g., progressive supranuclear palsy and frontotemporal dementia). The P301L mutation makes tau prone to aggregation; therefore, JNPL3 mice present a more challenging target than mouse models of human tau without mutations. JNPL3 mice were treated from 3 to 7 months of age with Vehicle, 30 mg/kg compound dose, or 40 mg/kg compound dose. Biochemical methods were used to evaluate self-associated tau, insoluble tau aggregates, total tau, and phosphorylated tau in the hindbrain, cortex, and hippocampus. The Vehicle group had higher levels of insoluble tau in the hindbrain than the Baseline group; treatment with 40 mg/kg compound dose prevented this increase. In the cortex, the levels of insoluble tau were similar in the Baseline and Vehicle groups, indicating that the pathological phenotype of these mice was beginning to emerge at the study endpoint and that there was a delay in the development of the phenotype of the model as originally characterized. No drug-related adverse effects were observed during the 4-month treatment period.

Asunto(s)

Enfermedades Neurodegenerativas , Tauopatías , Proteínas tau , Animales , Humanos , Ratones , Modelos Animales de Enfermedad , Ratones Transgénicos , Rombencéfalo/metabolismo , Proteínas tau/antagonistas & inhibidores , Proteínas tau/metabolismo , Tauopatías/tratamiento farmacológico , Tauopatías/prevención & control , Tauopatías/genética