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1.
Commun Biol ; 5(1): 1105, 2022 10 19.
Artículo en Inglés | MEDLINE | ID: mdl-36261573

RESUMEN

Patients with peripheral nerve injury, viral infection or metabolic disorder often suffer neuropathic pain due to inadequate pharmacological options for relief. Developing novel therapies has been challenged by incomplete mechanistic understanding of the cellular microenvironment in sensory nerve that trigger the emergence and persistence of pain. In this study, we report a high resolution transcriptomics map of the cellular heterogeneity of naïve and injured rat sensory nerve covering more than 110,000 individual cells. Annotation reveals distinguishing molecular features of multiple major cell types totaling 45 different subtypes in naïve nerve and an additional 23 subtypes emerging after injury. Ligand-receptor analysis revealed a myriad of potential targets for pharmacological intervention. This work forms a comprehensive resource and unprecedented window into the cellular milieu underlying neuropathic pain and demonstrates that nerve injury is a dynamic process orchestrated by multiple cell types in both the endoneurial and epineurial nerve compartments.


Asunto(s)
Neuralgia , Traumatismos de los Nervios Periféricos , Neuropatía Ciática , Ratas , Animales , Traumatismos de los Nervios Periféricos/genética , Traumatismos de los Nervios Periféricos/metabolismo , Nervio Ciático/lesiones , Ratas Sprague-Dawley , Ligandos , Análisis de la Célula Individual , Neuropatía Ciática/genética , Neuralgia/genética , Neuralgia/metabolismo
2.
Cold Spring Harb Protoc ; 2015(1): pdb.prot072439, 2015 Jan 05.
Artículo en Inglés | MEDLINE | ID: mdl-25561613

RESUMEN

The field of single-cell analysis has greatly benefitted from recent technological advances allowing scientists to study genomes, transcriptomes, proteomes, and metabolomes at the single-cell level. Transcriptomics allows a unique window into cell function and is especially useful for studying global variability among single cells of seemingly the same type. Generating transcriptome data from RNA samples has become increasingly easy and can be done using either microarray or RNA-Seq techniques. RNA isolation is the first step of transcriptomics. Numerous RNA isolation procedures exist and differ with respect to the type and number of cells from which they are capable of isolating RNA. Although it is trivial to isolate RNA from bulk tissue or culture plates, sophisticated methods are required to capture RNA from single cells in a pool of cells or in intact tissue. We describe here the protocols used for isolating the soma of single neurons in cultures and in tissue slices using the pipette capture and the PALM or laser capture microdissection (LCM) approaches, respectively. LCM was developed to isolate cells from tissue sections primarily for pathological tissue analysis. LCM can be used to isolate individual cells or groups of cells from ethanol or paraffin-embedded formalin-fixed tissue sections and dissociated tissue cultures. The soma isolates from either technique can subsequently be used for RNA amplification procedures and transcriptome analysis. These procedures can also be adapted to other cell types in cultures and tissue sections and can be used on neuronal subcellular structures, such as dendrites.


Asunto(s)
Técnicas de Cultivo de Célula/métodos , Captura por Microdisección con Láser , Neuronas/metabolismo , ARN/análisis , Animales , Técnicas de Cultivo de Célula/instrumentación , Células Cultivadas , Hipocampo/citología , Ratones , ARN/genética
3.
Nat Methods ; 11(2): 190-6, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24412976

RESUMEN

Transcriptome profiling of single cells resident in their natural microenvironment depends upon RNA capture methods that are both noninvasive and spatially precise. We engineered a transcriptome in vivo analysis (TIVA) tag, which upon photoactivation enables mRNA capture from single cells in live tissue. Using the TIVA tag in combination with RNA sequencing (RNA-seq), we analyzed transcriptome variance among single neurons in culture and in mouse and human tissue in vivo. Our data showed that the tissue microenvironment shapes the transcriptomic landscape of individual cells. The TIVA methodology is, to our knowledge, the first noninvasive approach for capturing mRNA from live single cells in their natural microenvironment.


Asunto(s)
Encéfalo/metabolismo , Perfilación de la Expresión Génica , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Hipocampo/metabolismo , Neuronas/metabolismo , Análisis de Secuencia de ARN/métodos , Animales , Biología Computacional , Biblioteca de Genes , Humanos , Ratones , Ratones Endogámicos C57BL , ARN Mensajero/genética
4.
Science ; 339(6116): 197-200, 2013 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-23307741

RESUMEN

An extensive literature shows that astrocytes exhibit metabotropic glutamate receptor 5 (mGluR5)-dependent increases in cytosolic calcium ions (Ca(2+)) in response to glutamatergic transmission and, in turn, modulate neuronal activity by their Ca(2+)-dependent release of gliotransmitters. These findings, based on studies of young rodents, have led to the concept of the tripartite synapse, in which astrocytes actively participate in neurotransmission. Using genomic analysis, immunoelectron microscopy, and two-photon microscopy of astrocytic Ca(2+) signaling in vivo, we found that astrocytic expression of mGluR5 is developmentally regulated and is undetectable after postnatal week 3. In contrast, mGluR3, whose activation inhibits adenylate cyclase but not calcium signaling, was expressed in astrocytes at all developmental stages. Neuroglial signaling in the adult brain may therefore occur in a manner fundamentally distinct from that exhibited during development.


Asunto(s)
Envejecimiento , Astrocitos/metabolismo , Señalización del Calcio , Corteza Cerebral/metabolismo , Ácido Glutámico/metabolismo , Receptores de Glutamato Metabotrópico/metabolismo , Adolescente , Animales , Calcio/metabolismo , Corteza Cerebral/citología , Corteza Cerebral/ultraestructura , Femenino , Hipocampo/citología , Hipocampo/metabolismo , Hipocampo/ultraestructura , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Receptor del Glutamato Metabotropico 5 , Receptores de Glutamato Metabotrópico/agonistas , Transmisión Sináptica
5.
J R Soc Interface ; 9(77): 3165-83, 2012 Dec 07.
Artículo en Inglés | MEDLINE | ID: mdl-22915636

RESUMEN

The building blocks of complex biological systems are single cells. Fundamental insights gained from single-cell analysis promise to provide the framework for understanding normal biological systems development as well as the limits on systems/cellular ability to respond to disease. The interplay of cells to create functional systems is not well understood. Until recently, the study of single cells has concentrated primarily on morphological and physiological characterization. With the application of new highly sensitive molecular and genomic technologies, the quantitative biochemistry of single cells is now accessible.


Asunto(s)
Neuronas/fisiología , Análisis de la Célula Individual/métodos , Electrofisiología , Regulación de la Expresión Génica , Hibridación in Situ , Canales Iónicos/fisiología , Neuronas/citología , Biosíntesis de Proteínas , Proteómica/métodos , Procesos Estocásticos , Transcriptoma
6.
Proc Natl Acad Sci U S A ; 109(16): 6265-70, 2012 Apr 17.
Artículo en Inglés | MEDLINE | ID: mdl-22421436

RESUMEN

Adenosine is a potent anticonvulsant acting on excitatory synapses through A1 receptors. Cellular release of ATP, and its subsequent extracellular enzymatic degradation to adenosine, could provide a powerful mechanism for astrocytes to control the activity of neural networks during high-intensity activity. Despite adenosine's importance, the cellular source of adenosine remains unclear. We report here that multiple enzymes degrade extracellular ATP in brain tissue, whereas only Nt5e degrades AMP to adenosine. However, endogenous A1 receptor activation during cortical seizures in vivo or heterosynaptic depression in situ is independent of Nt5e activity, and activation of astrocytic ATP release via Ca(2+) photolysis does not trigger synaptic depression. In contrast, selective activation of postsynaptic CA1 neurons leads to release of adenosine and synaptic depression. This study shows that adenosine-mediated synaptic depression is not a consequence of astrocytic ATP release, but is instead an autonomic feedback mechanism that suppresses excitatory transmission during prolonged activity.


Asunto(s)
Adenosina/metabolismo , Potenciales Postsinápticos Excitadores/fisiología , Retroalimentación Fisiológica/fisiología , Neuronas/metabolismo , 5'-Nucleotidasa/antagonistas & inhibidores , 5'-Nucleotidasa/genética , 5'-Nucleotidasa/metabolismo , Adenosina Difosfato/análogos & derivados , Adenosina Difosfato/farmacología , Adenosina Monofosfato/metabolismo , Adenosina Trifosfato/metabolismo , Animales , Astrocitos/metabolismo , Encéfalo/metabolismo , Encéfalo/fisiopatología , Región CA1 Hipocampal/citología , Región CA1 Hipocampal/metabolismo , Región CA1 Hipocampal/fisiología , Proteínas Ligadas a GPI/antagonistas & inhibidores , Proteínas Ligadas a GPI/genética , Proteínas Ligadas a GPI/metabolismo , Depresión Sináptica a Largo Plazo/fisiología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Técnicas de Placa-Clamp , Receptor de Adenosina A1/metabolismo , Convulsiones/metabolismo , Convulsiones/fisiopatología
7.
Neuron Glia Biol ; 6(2): 113-25, 2010 May.
Artículo en Inglés | MEDLINE | ID: mdl-20846463

RESUMEN

In well-differentiated primary cultures of mouse astrocytes, which express no serotonin transporter (SERT), the 'serotonin-specific reuptake inhibitor' (SSRI) fluoxetine leads acutely to 5-HT2B receptor-mediated, transactivation-dependent phosphorylation of extracellular regulated kinases 1/2 (ERK1/2) with an EC50 of ~5 µM, and chronically to ERK1/2 phosphorylation-dependent upregulation of mRNA and protein expression of calcium-dependent phospholipase A2 (cPLA2) with ten-fold higher affinity. This affinity is high enough that fluoxetine given therapeutically may activate astrocytic 5-HT2B receptors (Li et al., 2008, 2009). We now confirm the expression of 5-HT2B receptors in astrocytes freshly dissociated from mouse brain and isolated by fluorescence-activated cell sorting (FACS) and investigate in cultured cells if the effects of fluoxetine are shared by all five conventional SSRIs with sufficiently high affinity to be relevant for mechanism(s) of action of SSRIs. Phosphorylated and total ERK1/2 and mRNA and protein expression of cPLA2a were determined by Western blot and reverse transcription polymerase chain reaction (RT-PCR). Paroxetine, which differs widely from fluoxetine in affinity for SERT and for another 5-HT2 receptor, the 5-HT2C receptor, acted acutely and chronically like fluoxetine. One micromolar of paroxetine, fluvoxamine or sertraline increased cPLA2a expression during chronic treatment; citalopram had a similar effect at 0.1-0.5 µM; these are therapeutically relevant concentrations.


Asunto(s)
Astrocitos/efectos de los fármacos , Astrocitos/metabolismo , Encéfalo/metabolismo , Receptor de Serotonina 5-HT2B/genética , Receptor de Serotonina 5-HT2B/metabolismo , Inhibidores Selectivos de la Recaptación de Serotonina/farmacología , Animales , Encéfalo/citología , Células Cultivadas , Citometría de Flujo/métodos , Fluoxetina/farmacología , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Paroxetina/farmacología , Receptor de Serotonina 5-HT2B/biosíntesis , Transducción de Señal/efectos de los fármacos , Transducción de Señal/genética
8.
Neurochem Int ; 57(4): 411-20, 2010 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-20380860

RESUMEN

Recent in vivo studies have established astrocytes as a major target for locus coeruleus activation (Bekar et al., 2008), renewing interest in cell culture studies on noradrenergic effects on astrocytes in primary cultures and calling for additional information about the expression of adrenoceptor subtypes on different types of brain cells. In the present communication, mRNA expression of alpha(1)-, alpha(2)- and beta-adrenergic receptors and their subtypes was determined in freshly isolated, cell marker-defined populations of astrocytes, NG2-positive cells, microglia, endothelial cells, and Thy1-positive neurons (mainly glutamatergic projection neurons) in murine cerebral cortex. Immediately after dissection of frontal, parietal and occipital cortex of 10-12-week-old transgenic mice, which combined each cell-type marker with a specific fluorescent signal, the tissue was digested, triturated and centrifuged, yielding a solution of dissociated cells of all types, which were separated by fluorescence-activated cell sorting (FACS). mRNA expression in each cell fraction was determined by microarray analysis. alpha(1A)-Receptors were unequivocally expressed in astrocytes and NG2-positive cells, but absent in other cell types, and alpha(1B)-receptors were not expressed in any cell population. Among alpha(2)-receptors only alpha(2A)-receptors were expressed, unequivocally in astrocytes and NG-positive cells, tentatively in microglia and questionably in Thy1-positive neurons and endothelial cells. beta(1)-Receptors were unequivocally expressed in astrocytes, tentatively in microglia, and questionably in neurons and endothelial cells, whereas beta(2)-adrenergic receptors showed tentative expression in neurons and astrocytes and unequivocal expression in other cell types. This distribution was supported by immunochemical data and its relevance established by previous studies in well-differentiated primary cultures of mouse astrocytes, showing that stimulation of alpha(2)-adrenoceptors increases glycogen formation and oxidative metabolism, the latter by a mechanism depending on intramitochondrial Ca(2+), whereas alpha(1)-adrenoceptor stimulation enhances glutamate uptake, and beta-adrenoceptor activation causes glycogenolysis and increased Na(+), K(+)-ATPase activity. The Ca(2+)- and cAMP-mediated association between energy-consuming and energy-yielding processes is emphasized.


Asunto(s)
Astrocitos/metabolismo , Química Encefálica/genética , Química Encefálica/fisiología , Señalización del Calcio/fisiología , Receptores Adrenérgicos/biosíntesis , Receptores Adrenérgicos/genética , Animales , Separación Celular , Células Cultivadas , Citometría de Flujo , Expresión Génica/fisiología , Glucosa/metabolismo , Glucógeno/metabolismo , Ratones , Ratones Transgénicos/fisiología , Análisis por Micromatrices , Mitocondrias/metabolismo , Oxidación-Reducción , Ácido Pirúvico/metabolismo , ARN/biosíntesis , ARN/genética , Receptores Adrenérgicos alfa 1/biosíntesis , Receptores Adrenérgicos alfa 1/genética , Receptores Adrenérgicos alfa 2/biosíntesis , Receptores Adrenérgicos alfa 2/genética , Receptores Adrenérgicos beta/biosíntesis , Receptores Adrenérgicos beta/genética
9.
J Neurosci ; 28(18): 4702-11, 2008 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-18448647

RESUMEN

Astrocytes are electrically nonexcitable cells that communicate by means of Ca(2+) signaling. Long-distance intercellular Ca(2+) waves are initiated by release of ATP and activation of purinergic receptors on nearby cells. Previous studies have implicated connexin 43 (Cx43) in ATP release, but definitive proof that ATP exits through Cx43 hemichannels does not exist. Here, through several alternative approaches, we show that ATP anions can permeate through Cx43 hemichannels. First, openings of Cx43 hemichannels were detected in both cell-attached and inside-out patch recordings in C6 cells expressing Cx43, but not in C6 cells expressing Cx43-eGFP (enhanced green fluorescent protein) or a C-terminus truncation mutant of Cx43. Second, Cx43 hemichannel openings were inhibited by three structurally different gap-junction channel blockers, but not by the P2X(7) blocker Brilliant blue G. Third, bioluminescence imaging of ATP combined with single-channel recording in the inside-out patch configuration showed that ATP efflux coincided with channel openings and was absent when the Cx43 hemichannel was closed. Fourth, ion replacement experiments confirmed that Cx43 hemichannels are permeable to ATP. In summary, these observations provide the first direct evidence for efflux of ATP through Cx43 hemichannels. Furthermore, a putative Cx43 hemichannel with characteristics identical to the Cx43 hemichannel in C6 cells was identified in the membrane of hippocampal astrocytes in acutely prepared slices.


Asunto(s)
Adenosina Trifosfato/metabolismo , Conexina 43/metabolismo , Activación del Canal Iónico/fisiología , Adenosina Trifosfato/farmacología , Análisis de Varianza , Animales , Animales Recién Nacidos , Carbenoxolona/farmacología , Línea Celular Transformada , Conexina 43/genética , Relación Dosis-Respuesta en la Radiación , Estimulación Eléctrica/métodos , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Técnicas In Vitro , Activación del Canal Iónico/efectos de los fármacos , Mutación , Nitrobenzoatos/farmacología , Técnicas de Placa-Clamp , Bloqueadores de los Canales de Potasio/farmacología , Ratas , Ratas Sprague-Dawley , Tetraetilamonio/farmacología , Transfección/métodos
10.
J Neurosci ; 28(3): 681-95, 2008 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-18199768

RESUMEN

Preconditioning is an endogenous mechanism in which a nonlethal exposure increases cellular resistance to subsequent additional severe injury. Here we show that connexin 43 (Cx43) plays a key role in protection afforded by preconditioning. Cx43 null mice were insensitive to hypoxic preconditioning, whereas wild-type littermate mice exhibited a significant reduction in infarct volume after occlusion of the middle cerebral artery. In cultures, Cx43-deficient cells responded to preconditioning only after exogenous expression of Cx43, and protection was attenuated by small interference RNA or by channel blockers. Our observations indicate that preconditioning reduced degradation of Cx43, resulting in a marked increase in the number of plasma membrane Cx43 hemichannels. Consequently, efflux of ATP through hemichannels led to accumulation of its catabolic product adenosine, a potent neuroprotective agent. Thus, adaptive modulation of Cx43 can offset environmental stress by adenosine-mediated elevation of cellular resistance.


Asunto(s)
Conexina 43/fisiología , Precondicionamiento Isquémico , Regulación hacia Arriba/fisiología , Adenosina Trifosfato/farmacología , Animales , Animales Recién Nacidos , Astrocitos/metabolismo , Supervivencia Celular , Células Cultivadas , Conexina 43/deficiencia , Inhibidores Enzimáticos/farmacología , Proteínas Fluorescentes Verdes/genética , Peróxido de Hidrógeno/farmacología , Técnicas In Vitro , Infarto de la Arteria Cerebral Media/metabolismo , Infarto de la Arteria Cerebral Media/patología , Infarto de la Arteria Cerebral Media/prevención & control , Potenciales de la Membrana/efectos de los fármacos , Potenciales de la Membrana/fisiología , Potenciales de la Membrana/efectos de la radiación , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Técnicas de Placa-Clamp , ARN Interferente Pequeño/uso terapéutico , Ratas , Factores de Tiempo , Transfección/métodos , Regulación hacia Arriba/genética
11.
Nat Med ; 14(1): 75-80, 2008 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-18157140

RESUMEN

Deep brain stimulation (DBS) is a widely used neurosurgical approach to treating tremor and other movement disorders. In addition, the use of DBS in a number of psychiatric diseases, including obsessive-compulsive disorders and depression, is currently being tested. Despite the rapid increase in the number of individuals with surgically implanted stimulation electrodes, the cellular pathways involved in mediating the effects of DBS remain unknown. Here we show that DBS is associated with a marked increase in the release of ATP, resulting in accumulation of its catabolic product, adenosine. Adenosine A1 receptor activation depresses excitatory transmission in the thalamus and reduces both tremor- and DBS-induced side effects. Intrathalamic infusion of A1 receptor agonists directly reduces tremor, whereas adenosine A1 receptor-null mice show involuntary movements and seizure at stimulation intensities below the therapeutic level. Furthermore, our data indicate that endogenous adenosine mechanisms are active in tremor, thus supporting the clinical notion that caffeine, a nonselective adenosine receptor antagonist, can trigger or exacerbate essential tremor. Our findings suggest that nonsynaptic mechanisms involving the activation of A1 receptors suppress tremor activity and limit stimulation-induced side effects, thereby providing a new pharmacological target to replace or improve the efficacy of DBS.


Asunto(s)
Adenosina/metabolismo , Estimulación Encefálica Profunda , Temblor/terapia , Adenosina Trifosfato/metabolismo , Animales , Axones/metabolismo , Cerebelo/metabolismo , Electrofisiología , Femenino , Masculino , Ratones , Ratones Endogámicos C57BL , Modelos Biológicos , Receptor de Adenosina A1/metabolismo , Tálamo/metabolismo , Temblor/metabolismo
12.
J Neurosci ; 27(45): 12255-66, 2007 Nov 07.
Artículo en Inglés | MEDLINE | ID: mdl-17989291

RESUMEN

Protoplasmic astrocytes are critically important to energy metabolism in the CNS. Our current understanding of the metabolic interactions between neurons and glia is based on studies using cultured cells, from which mainly inferential conclusions have been drawn as to the relative roles of neurons and glia in brain metabolism. In this study, we used functional genomics to establish the relative compartmentalization of neuronal and astrocytic metabolic pathways in the adult brain. To this end, fluorescence-activated cell sorting was used to directly isolate neurons and protoplasmic astrocytes from the cortex of adult mice. Microarray analysis showed that astrocytes and neurons each express transcripts predicting individual self-sufficiency in both glycolysis and oxidative metabolism. Surprisingly, most enzymes in the tricarboxylic acid (TCA) cycle were expressed at higher relative levels in astrocytes than in neurons. Mass spectrometric analysis of the TCA cycle intermediates confirmed that freshly isolated adult astrocytes maintained an active TCA cycle, whereas immuno-electron microscopy revealed that fine astrocytic processes encompassing synapses contained a higher density of mitochondria than surrounding cells. These observations indicate that astrocytes exhibit robust oxidative metabolism in the intact adult brain and suggest a prominent contribution of astrocytic metabolism to functional brain imaging, including BOLD (blood-oxygen level-dependent) functional magnetic resonance imaging signals.


Asunto(s)
Astrocitos/fisiología , Corteza Cerebral/fisiología , Citoplasma/metabolismo , Perfilación de la Expresión Génica/métodos , Animales , Astrocitos/metabolismo , Astrocitos/ultraestructura , Corteza Cerebral/metabolismo , Corteza Cerebral/ultraestructura , Citoplasma/genética , Citoplasma/ultraestructura , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos
13.
Nat Neurosci ; 10(6): 754-62, 2007 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-17468748

RESUMEN

Cortical spreading depression (CSD) is a self-propagating wave of cellular depolarization that has been implicated in migraine and in progressive neuronal injury after stroke and head trauma. Using two-photon microscopic NADH imaging and oxygen sensor microelectrodes in live mouse cortex, we find that CSD is linked to severe hypoxia and marked neuronal swelling that can last up to several minutes. Changes in dendritic structures and loss of spines during CSD are comparable to those during anoxic depolarization. Increasing O2 availability shortens the duration of CSD and improves local redox state. Our results indicate that tissue hypoxia associated with CSD is caused by a transient increase in O2 demand exceeding vascular O2 supply.


Asunto(s)
Depresión de Propagación Cortical/fisiología , Hipoxia/patología , Hipoxia/fisiopatología , Animales , Astrocitos/metabolismo , Edema Encefálico/etiología , Corteza Cerebral/metabolismo , Corteza Cerebral/patología , Corteza Cerebral/fisiopatología , Circulación Cerebrovascular , Depresión de Propagación Cortical/efectos de los fármacos , Diagnóstico por Imagen , Electroencefalografía/métodos , Femenino , Flujometría por Láser-Doppler/métodos , Proteínas Luminiscentes/biosíntesis , Masculino , Potenciales de la Membrana/fisiología , Ratones , Ratones Transgénicos , NAD , Neuronas/metabolismo , Oxígeno/metabolismo , Oxígeno/farmacología , Técnicas de Placa-Clamp
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