O trabalho aqui descrito foi financiado pelo Departamento de Assuntos de Veteranos EUA Biomédica Laboratório de Pesquisa e Desenvolvimento BX001686-1A1 e VA Reabilitação de Investigação e Desenvolvimento.

1. Chapeamento e manutenção da cultura celular <ol><li> Quente de Dulbecco Modified Eagle Médium (DMEM) meio de cultura (DMEM + 10% FBS + 1% de Penicilina / Estreptomicina / Neomicina) a 37 ° C. </li><li> Obter estoque da A12 células congeladas de -80 ° C. </li><li> Descongelar rapidamente células em 37 ° C num banho de água; uma vez descongelado, suavemente as células de pipeta para transferir para um frasco de cultura ventilada 75 centímetros 2 e adicione 10 ml de meio de cultura. </li><li> Incubar balão durante a noite em 5% de CO2 a 37 ° C. Aspirar a mídia após 24 horas e substitua-o por meios frescos. Continuar as células crescer até 70-80% de confluência é obtido (2-3 dias de crescimento). </li></ol> 2. Contando e cultivo de células <ol><li> DMEM quente e solução de 1x-tripsina-EDTA a 37 ° C. </li><li> Aspirar a partir de meios de células e lava-se duas vezes com solução salina tamponada com fosfato estéril (PBS). </li><li> Adicionar 500 ul de solução de tripsina e incubar a 37 ° C durante 2-5 min. </li><li> Separarcélulas de balão, utilizando um raspador e suspender as células em 5 ml de meio. Passe células através de filtro e passar por filtro de células em um tubo de 50 ml limpo. Que precisa passar células através de filtro mais de uma vez, mas não repetir mais do que três vezes. </li><li> Contagem de células utilizando um hemocitómetro para determinar a quantidade de células de cultura para semear 6000 células / poço numa placa de preto ou branco 96 poços de fundo claro com paredes em um volume final de 100 ul de meio. Incubar a placa em 5% de CO 2, a 37 ° C durante 24 hr. </li></ol> 3. Determinação Viabilidade celular e caspase-3/7 Actividade <ol><li> Transferir PA para um frasco de 5 ml estéril de vidro e solubilizar em 100% de dimetilsulfóxido (DMSO). Diluir solução estoque PA 1:10 em DMSO e adicioná-lo ao pré-aquecido DMEM para obter uma concentração final de trabalho de 0,1 mM de PA. Para meios de controle, adicione a mesma concentração de DMSO que é adicionado à mídia contendo PA. </li><li> Remova a mídia em cada poço e substituir com 50 ul media + / -PA. Incubar a placa durante 2 horas em 5% de CO 2, a 37 ° C. Em seguida, adicionam-se 5 ul de reagente de resazurina e incubar durante 10 min à temperatura ambiente. </li><li> Usando um leitor de microplacas multimodo, ficha de fluorescência (560 EX / 590 EM) para medir a viabilidade celular. Os resultados são apresentados como unidades de fluorescência relativas (RFU). </li><li> Para a mesma placa, adicionar 55 ul de reagente de caspase e incubar à temperatura ambiente durante 2 horas. </li><li> Novamente usando o leitor de microplacas, ficha luminescência para medir a atividade da caspase-3/7. Os resultados são apresentados como unidades de luminescência relativa (RLU), com luminescência directamente proporcional à caspase-3/7 actividade. </li><li> Para normalizar a atividade da caspase-3/7 para contagem de células, divida a viabilidade celular (RFU) por caspase-3/7 atividade (RLU). </li></ol>

<ol>
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Os autores não têm conflitos de divulgar.

O ensaio multiplex é uma técnica bem aceite que tem sido utilizado por cientistas em numerosas aplicações tais como PCR, microarrays de imunodetecção, e outros métodos de detecção baseados em proteínas de 13, 14. Recentemente, ensaios de multiplexagem tornaram-se cada vez mais utilizado em experiências in vitro, baseados em placa e foram validados como um método acurado para avaliar a citotoxicidade e viabilidade 12. No protocolo anterior, que demonstram a eficácia de lâmpada...

Dietas ricas em ácidos graxos saturados, como o ácido palmítico (PA) têm sido associados a obesidade e outras comorbidades, como doenças cardiovasculares e diabetes 1, 2. Dietas ricas em gordura também foram mostrados para aumentar o estresse oxidativo, apoptose e degeneração neuronal no hipotálamo, um importante regulador do apetite e gasto energético 3-7. Compreender o mecanismo através do qual a exposição dieta rica em gordura induz desregulação hipotalâmica é, portanto, importante para o desenvolvimento de tratamentos farmacológicos para a obesidade. No entanto, os mecanismos celulares pelos quais a gordura na dieta afeta a função neuronal permanecem obscuros. Uma melhor compreensão de como gorduras, como PA pode desencadear o início de vias apoptóticas hipotálamo é um primeiro passo necessário em direção a esse objetivo. O objetivo deste artigo é descrever um ensaio multiplex para testes in vitro de resposta neuronal à exposição PA, desenvolvido para uso em estudos de hneurodegeneração ypothalamic. Fornecemos uma descrição detalhada de um formato de 96 poços de ensaio multiplex in vitro para medir a caspase 3/7 actividade por número total de células de uma linha imortalizada diferenciadas célula hipotalâmica do rato adulto (designado A12) após o desafio oxidativo com PA 8. Resumidamente, a viabilidade celular é determinada após o desafio com PA através de um ensaio baseado resazurina. Resazurina é um composto permeável célula que sofre redução enzimática em células metabolicamente activas, um processo que se pensa ocorrer por meio da mitocôndria 9. As células viáveis ​​converter continuamente resazurina a resorufina, a produção de um sinal fluorescente proporcional à quantidade de células viáveis. Actividade da caspase-3/7 é então analisado utilizando um ensaio baseado lumogenic-DEVD. DEVD é uma sequência de aminoácidos (Asp-Glu-Val-Asp) clivada pela caspase-3. Quando esta sequência é acoplado a uma substância lumogenic, aquando da activação intracelular de caspase-3/7 e subsequente clivagemde substrato DEVD, o produto luminescente é liberada. Esta reacção é proporcional à actividade da caspase e, consequentemente, para a indução de apoptose. Como as células mortas não podem produzir caspase, caspase-3/7 atividade é de natureza transitória; portanto, a análise deve ser concluída entre 30 minutos a 4 horas após o desafio, dependendo da eficácia do estressor celular. A viabilidade das células é inversamente proporcional à actividade da caspase-3/7 e pode ser usado para determinar os mecanismos de morte celular. Por exemplo, este método tem sido utilizado para demonstrar que o pré-tratamento com a hormona peptídica orexina reduz a apoptose em células do hipotálamo desafiados com peróxido de hidrogénio, o que sugere que os mecanismos afectadas por este tratamento são importantes para a protecção contra danos oxidativos 10. É importante notar estes ensaios são linha e células dependente de tecido, uma vez que dependem de actividade mitocondrial para reduzir os reagentes do ensaio. Este protocolo foi otimizado para rato adulto hipotálamo (A12) células; no entanto,métodos descritos podem ser alterados para se ajustar dentro do âmbito da investigação semelhante. Os ensaios de multiplexação de um único poço de cultura proporciona uma vantagem em relação ao método tradicional de realização de ensaios individuais para várias razões. Além da economia de tempo, amostras de células, e os reagentes de cultura, ensaios de multiplexação também pode proporcionar conhecimentos sobre a sobrevivência das células e a morte, fornecem controlos internos, e eliminar a necessidade de experiências repetidas 11, 12. Métodos alternativos têm invocado borrões ou ELISAs ocidentais, que são ensaios de confiança, mas é dispendioso e consome tempo (1-2 dias), especialmente quando se utiliza um formato de 96 poços. Excluindo o tempo que leva para as células de cultura para o ensaio de multiplexagem, o tempo total é menos do que 3 horas. Embora este protocolo foi optimizado para utilização com células A12, pode ser alterada para uso em outros modelos, mantendo em mente os fatores que podem influenciar a integridade celular. Determineração se este protocolo iria trabalhar para uma série de experimentos depende do número de amostras ou condições experimentais e em experimentos a jusante planejadas.

<table border="0" cellpadding="0" cellspacing="0" width="723">
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:268px;">Adult Mouse Hypothalamus Cell Line mHypoA-1/2&#160;</td>
			<td style="width:137px;">Cellutions Biosystems Inc.</td>
			<td style="width:151px;">CLU172</td>
			<td style="width:167px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:268px;">Dulbecco&#8217;s Modified Eagle&#8217;s Medium</td>
			<td style="width:137px;">Invitrogen</td>
			<td style="width:151px;">10313-039</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:268px;">Fetal bovine serum&#160;</td>
			<td style="width:137px;">PAA Labs</td>
			<td style="width:151px;">A15-751</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:268px;">Penicillin/Streptomycin</td>
			<td style="width:137px;">Invitrogen</td>
			<td style="width:151px;">15070-063</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:268px;">Palmitic Acid</td>
			<td style="width:137px;">Sigma-Aldrich</td>
			<td style="width:151px;">P0500</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:268px;">Dimethy sulfoxide&#160;</td>
			<td style="width:137px;">Sigma-Aldrich</td>
			<td style="width:151px;">D2650</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:268px;"> 
			PrestoBlue Cell Viability Reagent</td>
			<td style="width:137px;">Invitrogen</td>
			<td>A13262</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:268px;">Caspase-Glo 3/7 Assay Systems</td>
			<td style="width:137px;">Promega</td>
			<td style="width:151px;">G8091</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:268px;">Equipment</td>
			<td style="width:137px;"></td>
			<td style="width:151px;"></td>
			<td></td>
		</tr>
		<tr height="63">
			<td height="63" style="height:63px;width:268px;">96W Optical Bottom Plate, Black Polystyrene, Cell Culture Treated, with lid, Sterile</td>
			<td style="width:137px;">Thermo Fisher Scientific</td>
			<td style="width:151px;">165305</td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:268px;">SpectraMax M5 Multi-Mode Microplate</td>
			<td style="width:137px;">Molecular Devices</td>
			<td style="width:151px;"></td>
			<td></td>
		</tr>
	</tbody>
</table>

use of a caspase multiplexing assay to determine apoptosis in a hypothalamic cell model

A capacidade de multiplexar os ensaios em estudos de mecanismos celulares complexas elimina a necessidade de experiências repetitivas, fornece os controlos internos, e diminui os custos e desperdícios de reagentes. Aqui descrevemos optimização de um ensaio multiplex para avaliar a apoptose após um ácido palmítico (PA) desafio em um modelo in vitro do hipotálamo, usando tanto fluorescentes e luminescentes baseados ensaios para medir a contagem de células viáveis ​​e caspase-3/7 em actividade de 96 poços formato de placa de microtitulação. A seguir ao desafio PA, as células viáveis ​​foram determinados por um ensaio fluorescente baseado em resazurina. A caspase-3/7 actividade foi determinada usando um substrato luminogenic, DEVD, e normalizada para o número de células, em seguida. Este ensaio de multiplexação é uma técnica útil para determinar as alterações na actividade da caspase após o estímulo por apoptose, tais como desafio ácido gordo saturado. O ácido gordo saturado PA pode aumentar o stress oxidativo e apoptose hipotalâmico, indicando o potencial importance de ensaios tais como os descritos aqui em estudar a relação entre os ácidos gordos saturados e função neuronal.

O protocolo acima descreve resultados na multiplexação de dois ensaios separados para determinar os mecanismos de morte celular. Figura 1 mostra uma visão geral do protocolo para determinar a viabilidade celular e caspase-3/7 atividade. Actividade de caspase foi significativamente aumentada em células desafiadas com PA após 2 horas de incubação (Figura 2A e na Tabela 1). A perda da integridade da membrana celular é uma alteração morfológica associada com a in...

Watch this Scientific Journal Video about Use of a Caspase Multiplexing Assay to Determine Apoptosis in a Hypothalamic Cell Model at JoVE.com

Use of a Caspase Multiplexing Assay to Determine Apoptosis in a Hypothalamic Cell Model

Ensaios Multiplex pode fornecer informações úteis para os mecanismos celulares básicos e eliminar o desperdício de reagentes e experiências repetitivas desnecessárias. Descrevemos aqui um ensaio multiplex atividade caspase-3/7, usando métodos fluorescentes e luminescentes à base, para determinar a viabilidade celular em um modelo in vitro hipotálamo seguinte desafio oxidativo com ácido palmítico.

Utilização de uma caspase Multiplexing ensaio para determinar a apoptose em um modelo de célula hipotalâmica

The ability to multiplex assays in studies of complex cellular mechanisms eliminates the need for repetitive experiments, provides internal controls, and ...

use-caspase-multiplexing-assay-to-determine-apoptosis-hypothalamic

Research

JoVE Journal

Neuroscience

14.9K visualizações.  Minneapolis Veterans Affairs Health Care System.  Ensaios Multiplex pode fornecer informações úteis para os mecanismos celulares básicos e eliminar o desperdício de reagentes e experiências repetitivas desnecessárias. Descrevemos aqui um ensaio multiplex atividade caspase-3/7, usando métodos fluorescentes e luminescentes à base, para determinar a viabilidade celular em um modelo in vitro hipotálamo seguinte desafio oxidativo com ácido palmítico. 

Vídeo: Use of a Caspase Multiplexing Assay to Determine Apoptosis in a Hypothalamic Cell Model

Optic Nerve Transection: A Model of Adult Neuron Apoptosis in the Central Nervous System

Retinal ganglion cells (RGCs) are CNS neurons that output visual information from the retina to the brain, via the optic nerve. 
The optic nerve can be accessed within the orbit of the eye and completely transected (axotomized), cutting the axons of the entire RGC population. Optic nerve 
transection is a reproducible model of apoptotic neuronal cell death in the adult CNS 1-4. This model is particularly attractive because the vitreous
 chamber of the eye acts as a capsule for drug delivery to the retina, permitting experimental manipulations via intraocular injections. The diffusion of chemicals 
through the vitreous fluid ensures that they act upon the entire RGC population. Moreover, RGCs can be selectively transfected by applying short interfering RNAs 
(siRNAs), plasmids, or viral vectors to the cut end of the optic nerve 5-7 or injecting vectors into their target, the superior colliculus 8. 
This allows researchers to study apoptotic mechanisms in the desired neuronal population without confounding effects on other bystander neurons or surrounding glia. 
An additional benefit is the ease and accuracy with which cell survival can be quantified after injury. The retina is a flat, layered tissue and RGCs are localized in 
the innermost layer, the ganglion cell layer. The survival of RGCs can be tracked over time by applying a fluorescent tracer (3% Fluorogold) to the cut end of the 
optic nerve at the time of axotomy, or by injecting the tracer into the superior colliculus (RGC target) one week prior to axotomy. The tracer is retrogradely transported, labeling 
the entire RGC population. Because the ganglion cell layer is a monolayer (one cell thick), RGC densities can be quantified in flat-mounted tissue, without the need 
for stereology. Optic nerve transection leads to the apoptotic death of 90% of injured RGCs within 14 days postaxotomy 9-11. RGC apoptosis has a 
characteristic time-course whereby cell death is delayed 3-4 days postaxotomy, after which the cells rapidly degenerate. This provides a time window for 
experimental manipulations directed against pathways involved in apoptosis.

Optic Nerve transection is a widely used model of adult CNS injury. Ninety percent of retinal ganglion cells (RGCs) whose axons are completely transected (axotomy) die within 14 days after axotomy. This model is easily amenable to experimental manipulations and highly reproducible.

Transecção do nervo óptico: Um Modelo de Apoptose Neuron Adultos no Sistema Nervoso Central

Retinal ganglion cells (RGCs) are CNS neurons that output visual information from the retina to the brain, via the optic nerve. 
The optic nerve can be ...

Neurociência

Neural-Colony Forming Cell Assay: An Assay To Discriminate Bona Fide Neural Stem Cells from Neural Progenitor Cells

The neurosphere assay (NSA) is one of the most frequently used methods to isolate, expand and also calculate the frequency of neural stem cells (NSCs). Furthermore, this serum-free culture system has also been employed to expand stem cells and determine their frequency from a variety of tumors and normal tissues. It has been shown recently that a one-to-one relationship does not exist between neurosphere formation and NSCs. This suggests that the NSA as currently applied, overestimates the frequency of NSCs in a mixed population of neural precursor cells isolated from both the embryonic and adult mammalian brain. This video practically demonstrates a novel collagen based semi- solid assay, the neural-colony forming cell assay (N-CFCA), which has the ability to discriminate stem from progenitor cells based on their long-term proliferative potential, and thus provides a method to enumerate NSC frequency. In the N-CFCA, colonies &ge;2 mm in diameter are derived from cells that meet all the functional criteria of a NSC, while colonies &lt; 2mm are derived from progenitors. The N-CFCA procedure can be used for cells prepared from different sources including primary and cultured adult or embryonic mouse CNS cells. Here we use cells prepared from passage one neurospheres generated from embryonic day 14 mice brain to perform N-CFCA. The cultures are replenished with proliferation medium every seven days for three weeks to allow the plated cells to exhibit their full proliferative potential and then the frequency of neural progenitor and bona fide neural stem cells is calculated respectively by counting the number of colonies that are &lt; 2mm and the ones that are &ge;2mm in reference to the number of cells that were initially plated.

This video protocol demonstrates how to discriminate and enumerate bona fide neural stem cells in a mixed population of neural precursor cells using the neural colony-forming cell assay.

Neurais Colony-Forming Assay Cell: um ensaio para Discriminar Bona Fide células-tronco neurais de células progenitoras neurais

The neurosphere assay (NSA) is one of the most frequently used methods to isolate, expand and also calculate the frequency of neural stem cells (NSCs). ...

Monitoring Cleaved Caspase-3 Activity and Apoptosis of Immortalized Oligodendroglial Cells using Live-cell Imaging and Cleaveable Fluorogenic-dye Substrates Following Potassium-induced Membrane Depolarization

The central nervous system can experience a number of stresses and neurological insults, which can have numerous adverse effects that ultimately lead to a reduction in neuronal population and function. Damaged axons can release excitatory molecules including potassium or glutamate into the extracellular matrix, which in turn, can produce further insult and injury to the supporting glial cells including astrocytes and oligodendrocytes 8, 16. If the insult persists, cells will undergo programmed cell death (apoptosis), which is regulated and activated by a number of well-established signal transduction cascades 14. Apoptosis and tissue necrosis can occur after traumatic brain injury, cerebral ischemia, and seizures. A classical example of apoptotic regulation is the family of cysteine-dependent aspartate-directed proteases, or caspases. Activated proteases including caspases have also been implicated in cell death in response to chronic neurodegenerative diseases including Alzheimer's, Huntington's, and Multiple Sclerosis 4, 14, 3, 11, 7.
In this protocol we describe the use of the NucView 488 caspase-3 substrate to measure the rate of caspase-3 mediated apoptosis in immortalized N19-oligodendrocyte (OLG) cell cultures 15, 5, following exposure to different extracellular stresses such as high concentrations of potassium or glutamate. The conditionally-immortalized N19-OLG cell line (representing the O2A progenitor) was obtained from Dr. Anthony Campagnoni (UCLA Semel Institute for Neuroscience) 15, 5, and has been previously used to study molecular mechanisms of myelin gene expression and signal transduction leading to OLG differentiation (e.g.6, 10). We have found this cell line to be robust with respect to transfection with exogenous myelin basic protein (MBP) constructs fused to either RFP or GFP (red or green fluorescent protein) 13, 12. Here, the N19-OLG cell cultures were treated with either 80 mM potassium chloride or 100 mM sodium glutamate to mimic axonal leakage into the extracellular matrix to induce apoptosis 9. We used a bi-functional caspase-3 substrate containing a DEVD (Asp-Glu-Val-Asp) caspase-3 recognition subunit and a DNA-binding dye 2. The substrate quickly enters the cytoplasm where it is cleaved by intracellular caspase-3. The dye, NucView 488 is released and enters the cell nucleus where it binds DNA and fluoresces green at 488 nm, signaling apoptosis. Use of the NucView 488 caspase-3 substrate allows for live-cell imaging in real-time 1, 10. In this video, we also describe the culturing and transfection of immortalized N19-OLG cells, as well as live-cell imaging techniques.

Monitoring Cleaved Caspase-3 Activity and Apoptosis of Immortalized Oligodendroglial Cells using Live-cell Imaging and Cleaveable Fluorogenic-dye Substrates Following Potassium-induced Membrane Depola

Live-cell imaging of caspase-3 mediated apoptosis in immortalized N19-oligodendrocyte cell cultures using the NucView 488 caspase-3 substrate. This technique is applicable for programmed cell death assays in real-time in a variety of cell types and tissues.

Monitoramento de Atividades de caspase-3 Clivadas e apoptose das células oligodendrogliais Imortalizado usando Live-célula Imaging and Cleaveable Fluorogênico-dye seguintes substratos de potássio induzida por despolarização da membrana

The central nervous system can experience a number of stresses and neurological insults, which can have numerous adverse effects that ultimately lead to a ...

Functional Interrogation of Adult Hypothalamic Neurogenesis with Focal Radiological Inhibition

The functional characterization of adult-born neurons remains a significant challenge. Approaches to inhibit adult neurogenesis via invasive viral delivery or transgenic animals have potential confounds that make interpretation of results from these studies difficult. New radiological tools are emerging, however, that allow one to noninvasively investigate the function of select groups of adult-born neurons through accurate and precise anatomical targeting in small animals. Focal ionizing radiation inhibits the birth and differentiation of new neurons, and allows targeting of specific neural progenitor regions. In order to illuminate the potential functional role that adult hypothalamic neurogenesis plays in the regulation of physiological processes, we developed a noninvasive focal irradiation technique to selectively inhibit the birth of adult-born neurons in the hypothalamic median eminence. We describe a method for Computer tomography-guided focal irradiation (CFIR) delivery to enable precise and accurate anatomical targeting in small animals. CFIR uses three-dimensional volumetric image guidance for localization and targeting of the radiation dose, minimizes radiation exposure to nontargeted brain regions, and allows for conformal dose distribution with sharp beam boundaries. This protocol allows one to ask questions regarding the function of adult-born neurons, but also opens areas to questions in areas of radiobiology, tumor biology, and immunology. These radiological tools will facilitate the translation of discoveries at the bench to the bedside.

The function of adult-born mammalian neurons remains an active area of investigation. Ionizing radiation inhibits the birth of new neurons. Using computer tomography-guided focal irradiation (CFIR), three-dimensional anatomical targeting of specific neural progenitor populations can now be used to assess the functional role of adult neurogenesis.

Interrogatório funcional do Adulto Hypothalamic Neurogenesis com Focal Radiológica Inibição

The functional characterization of adult-born neurons remains a significant challenge. Approaches to inhibit adult neurogenesis via invasive viral ...

A Novel Light Damage Paradigm for Use in Retinal Regeneration Studies in Adult Zebrafish

Light-induced retinal degeneration (LIRD) is commonly used in both rodents and zebrafish to damage rod and cone photoreceptors. In adult zebrafish, photoreceptor degeneration triggers M&#252;ller glial cells to re-enter the cell cycle and produce transient-amplifying progenitors. These progenitors continue to proliferate as they migrate to the damaged area, where they ultimately give rise to new photoreceptors. Currently, there are two widely-used LIRD paradigms, each of which results in varying degrees of photoreceptor loss and corresponding differences in the regeneration response. As more genetic and pharmacological tools are available to test the role of individual genes of interest during regeneration, there is a need to develop a robust LIRD paradigm. Here we describe a LIRD protocol that results in widespread and consistent loss of both rod and cone photoreceptors in which we have combined the use of two previously established LIRD techniques. Furthermore, this protocol can be extended for use in pigmented animals, which eliminates the need to maintain transgenic lines of interest on the albino background for LIRD studies.

Multiple light damage protocols have been described to damage photoreceptors and consequently induce a retinal regeneration response in adult zebrafish. This protocol describes an improved method that can be used in pigmented animals and that damages the vast majority of rod and cone photoreceptors across the entire retina.

A Light Novel danos Paradigma para uso em estudos de regeneração da retina em Zebrafish Adulto

Light-induced retinal degeneration (LIRD) is commonly used in both rodents and zebrafish to damage rod and cone photoreceptors. In adult zebrafish, ...

Microglia as a Surrogate Biosensor to Determine Nanoparticle Neurotoxicity

Nanoparticles found in air pollutants can alter neurotransmitter profiles, increase neuroinflammation, and alter brain function. Therefore, the assay described here will aid in elucidating the role of microglia in neuroinflammation and neurodegenerative diseases. The use of microglia, resident immune cells of the brain, as a surrogate biosensor provides novel insight into how inflammatory responses mediate neuronal insults. Here, we utilize an immortalized murine microglial cell line, designated BV2, and describe a method for nanoparticle exposure using silver nanoparticles (AgNPs) as a standard. We describe how to expose microglia to nanoparticles, how to remove nanoparticles from supernatant, and how to use supernatant from activated microglia to determine toxicity, using hypothalamic cell survival as a measure. Following AgNP exposure, BV2 microglial activation was validated using a tumor necrosis factor alpha (TNF-&#945;) enzyme linked immunosorbent assay (ELISA). The supernatant was filtered to remove the AgNP and to allow cytokines and other secreted factors to remain in the conditioned media. Hypothalamic cells were then exposed to supernatant from AgNP activated microglia and survival of neurons was determined using a resazurin-based fluorescent assay. This technique is useful for utilizing microglia as a surrogate biomarker of neuroinflammation and determining the effect of neuroinflammation on other cell types.

Microglia (immune cells of the brain), are used as a surrogate biosensor to determine how nanoparticles influence neurotoxicity. We describe a series of experiments designed to assay microglial response to nanoparticles and exposure of hypothalamic neurons to supernatant from activated microglia to determine neurotoxicity.

Microglia como um Biosensor Surrogate determinar nanopartículas neurotoxicidade

Nanoparticles found in air pollutants can alter neurotransmitter profiles, increase neuroinflammation, and alter brain function. Therefore, the assay ...

The Use of Trace Eyeblink Classical Conditioning to Assess Hippocampal Dysfunction in a Rat Model of Fetal Alcohol Spectrum Disorders

Neonatal rats were administered a relatively high concentration of ethyl alcohol (11.9% v/v) during postnatal days 4-9, a time when the fetal brain undergoes rapid organizational change and is similar to accelerated brain changes that occur during the third trimester in humans. This model of fetal alcohol spectrum disorders (FASDs) produces severe brain damage, mimicking the amount and pattern of binge-drinking that occurs in some pregnant alcoholic mothers. We describe the use of trace eyeblink classical conditioning (ECC), a higher-order variant of associative learning, to assess long-term hippocampal dysfunction that is typically seen in alcohol-exposed adult offspring. At 90 days of age, rodents were surgically prepared with recording and stimulating electrodes, which measured electromyographic (EMG) blink activity from the left eyelid muscle and delivered mild shock posterior to the left eye, respectively. After a 5 day recovery period, they underwent 6 sessions of trace ECC to determine associative learning differences between alcohol-exposed and control rats. Trace ECC is one of many possible ECC procedures that can be easily modified using the same equipment and software, so that different neural systems can be assessed. ECC procedures in general, can be used as diagnostic tools for detecting neural pathology in different brain systems and different conditions that insult the brain.

Trace eyeblink classical conditioning (ECC) was used to assess hippocampal-dependent associative learning in adult rats that were administered a high concentration (11.9% v/v) of alcohol during early neonatal brain development. In general, ECC procedures are sound diagnostic tools for detecting brain dysfunction across many psychological and biomedical settings.

O uso do condicionamento de rastreamento Eyeblink clássico para avaliar disfunção Hippocampal em um modelo do rato de transtornos do espectro do álcool Fetal

Neonatal rats were administered a relatively high concentration of ethyl alcohol (11.9% v/v) during postnatal days 4-9, a time when the fetal brain ...

Live-cell Measurement of Odorant Receptor Activation Using a Real-time cAMP Assay

The enormous sizes of the mammalian odorant receptor (OR) families present difficulties to find their cognate ligands among numerous volatile chemicals. To efficiently and accurately deorphanize ORs, we combine the use of a heterologous cell line to express mammalian ORs and a genetically modified biosensor plasmid to measure cAMP production downstream of OR activation in real time. This assay can be used to screen odorants against ORs and vice versa. Positive odorant-receptor interactions from the screens can be subsequently confirmed by testing against various odor concentrations, generating concentration-response curves. Here we used this method to perform a high-throughput screening of an odorous compound against a human OR library expressed in Hana3A cells and confirmed that the positively-responding receptor is the cognate receptor for the compound of interest. We found this high-throughput detection method to be efficient and reliable in assessing OR activation and our data provide an example of its potential use in OR functional studies.

Characterizing the function of odorant receptors serves an indispensable part in the deorphanization process. We describe a method to measure the activation of odorant receptors in real time using a cAMP assay.

Viver-pilha medição de odorante Receptor de ativação usando um ensaio de campo em tempo real

The enormous sizes of the mammalian odorant receptor (OR) families present difficulties to find their cognate ligands among numerous volatile chemicals. ...

A Protocol for Measuring Cue Reactivity in a Rat Model of Cocaine Use Disorder

Cocaine use disorder (CUD) follows a trajectory of repetitive self-administration during which previously neutral stimuli gain incentive value. Cue reactivity, the sensitivity to cues previously linked with the drug-taking experience, plays a prominent role in human craving during abstinence. Cue reactivity can be assessed as the attentional orientation toward drug-associated cues that is measurable as appetitive approach behavior in both preclinical and human studies. Herein describes an assessment of cue reactivity in rats trained to self-administer cocaine. Cocaine self-administration is paired with the presentation of discrete cues that act as conditioned reinforcers (i.e., house light, stimulus light, infusion pump sounds). Following a period of abstinence, lever presses in the cocaine self-administration context accompanied by the discrete cues previously paired with cocaine infusion are measured as cue reactivity. This model is useful to explore neurobiological mechanisms underlying cue reactivity processes as well as to assess pharmacotherapies to suppress cue reactivity and therefore, modify relapse vulnerability. Advantages of the model include its translational relevance, and its face and predictive validities.&#160;The primary limitation of the model is that the cue reactivity task can only be performed infrequently and must only be used in short duration (e.g., 1 hour), otherwise rats will begin to extinguish the pairing of the discrete cues with the cocaine stimulus. The model is extendable to any positively reinforcing stimulus paired with discrete cues; though particularly applicable to drugs of abuse, this model may hold future applications in fields such as obesity, where palatable food rewards can act as positively reinforcing stimuli.

Cue reactivity is conceptualized as sensitivity to cues linked with drug-taking experiences that contribute to craving and relapse in abstinent humans. Cue reactivity is modeled in rats by measuring attentional orientation toward drug-associated cues that results in appetitive approach behavior in a cue reactivity test following self-administration and forced abstinence.

Um protocolo para medição de reatividade de Cue em um modelo do rato do transtorno de uso de cocaína

Cocaine use disorder (CUD) follows a trajectory of repetitive self-administration during which previously neutral stimuli gain incentive value. Cue ...

A Neurosphere Assay to Evaluate Endogenous Neural Stem Cell Activation in a Mouse Model of Minimal Spinal Cord Injury

Neural stem cells (NSCs) in the adult mammalian spinal cord are a relatively mitotically quiescent population of periventricular cells that can be studied in vitro using the neurosphere assay. This colony-forming assay is a powerful tool to study the response of NSCs to exogenous factors in a dish; however, this can also be used to study the effect of in vivo manipulations with the proper understanding of the strengths and limitations of the assay. One manipulation of the clinical interest is the effect of injury on endogenous NSC activation. Current models of spinal cord injury provide a challenge to study this as the severity of common contusion, compression, and transection models cause the destruction of the NSC niche at the site of the injury where the stem cells reside. Here, we describe a minimal injury model that causes localized damage at the superficial dorsolateral surface of the lower thoracic level (T7/8) of the adult mouse spinal cord. This injury model spares the central canal at the level of injury and permits analysis of the NSCs that reside at the level of the lesion at various time points following injury. Here, we show how the neurosphere assay can be utilized to study the activation of the two distinct, lineally-related, populations of NSCs that reside in the spinal cord periventricular region - primitive and definitive NSCs (pNSCs and dNSCs, respectively). We demonstrate how to isolate and culture these NSCs from the periventricular region at the level of injury and the white matter injury site. Our post-surgical spinal cord dissections show increased numbers of pNSC and dNSC-derived neurospheres from the periventricular region of injured cords compared to controls, speaking to their activation via injury. Furthermore, following injury, dNSC-derived neurospheres can be isolated from the injury site &#8212; demonstrating the ability of NSCs to migrate from their periventricular niche to sites of injury.

Here, we demonstrate the performance of a minimal spinal cord injury model in an adult mouse that spares the central canal niche housing endogenous neural stem cells (NSCs). We show how the neurosphere assay can be used to quantify activation and migration of definitive and primitive NSCs following injury.

Um ensaio de Neurosphere para avaliar a ativação de células-tronco neurais endógena em um modelo do rato da lesão medular mínima

Neural stem cells (NSCs) in the adult mammalian spinal cord are a relatively mitotically quiescent population of periventricular cells that can be studied ...