Name: three-dimensional confocal analysis of microglia/macrophage markers of polarization in experimental brain injury
Uploaded: 2013-09-04T13:00:00
Description: Watch this Scientific Journal Video about Three-dimensional Confocal Analysis of Microglia/macrophage Markers of Polarization in Experimental Brain Injury at JoVE.com

Stefano Fumagalli is a fellow of the Monzino Foundation.

1. Immunofluorescence
The following protocol is performed on coronal brain cryosections obtained from transcardially perfused mice (20 ml of PBS, 0.1 mol/liter, pH 7.4, followed by 50 ml of chilled paraformaldehyde 4% in PBS). After perfusion, brains are carefully removed and transferred to 30% sucrose in PBS at 4 &#176;C overnight for cryoprotection. The brains are then rapidly frozen by immersion in isopentane at - 45 &#176;C for 3 min before being sealed into vials and stored at -70 &#176;C u...

<ol>
	<li>Davalos, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=ATP+mediates+rapid+microglial+response+to+local+brain+injury+in+vivo.">ATP mediates rapid microglial response to local brain injury in vivo.</a> Nat. Neurosci. 8, 752-758 (2005).</li><li>Yenari, M. A., Kauppinen, T. M., Swanson, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microglial+activation+in+stroke:+therapeutic+targets.">Microglial activation in stroke: therapeutic targets.</a> Neurotherapeutics. 7, 378-391 (2010).</li><li>Iadecola, C., Anrather, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+immunology+of+stroke:+from+mechanisms+to+translation.">The immunology of stroke: from mechanisms to translation.</a> Nat. Med. 17, 796-808 (2011).</li><li>Jin, R., Yang, G., Li, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inflammatory+mechanisms+in+ischemic+stroke:+role+of+inflammatory+cells.">Inflammatory mechanisms in ischemic stroke: role of inflammatory cells.</a> J. Leukoc. Biol. 87, 779-789 (2010).</li><li>Schilling, M., Besselmann, M., Muller, M., Strecker, J. K., Ringelstein, E. B., Kiefer, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Predominant+phagocytic+activity+of+resident+microglia+over+hematogenous+macrophages+following+transient+focal+cerebral+ischemia:+an+investigation+using+green+fluorescent+protein+transgenic+bone+marrow+chimeric+mice.">Predominant phagocytic activity of resident microglia over hematogenous macrophages following transient focal cerebral ischemia: an investigation using green fluorescent protein transgenic bone marrow chimeric mice.</a> Exp. Neurol. 196, 290-297 (2005).</li><li>Perego, C., Fumagalli, S., De Simoni, M. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Temporal+pattern+of+expression+and+colocalization+of+microglia/macrophage+phenotype+markers+following+brain+ischemic+injury+in+mice.">Temporal pattern of expression and colocalization of microglia/macrophage phenotype markers following brain ischemic injury in mice.</a> Journal of Neuroinflammation. 8, 174-193 (2011).</li><li>Zanier, E. R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+umbilical+cord+blood+mesenchymal+stem+cells+protect+mice+brain+after+trauma.">Human umbilical cord blood mesenchymal stem cells protect mice brain after trauma.</a> Crit. CareMed. 39 (11), 2501-2510 (2011).</li><li>Capone, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neurosphere+derived+cells+exert+a+neuroprotective+action+by+changing+the+ischemic+microenvironment.">Neurosphere derived cells exert a neuroprotective action by changing the ischemic microenvironment.</a> PLoS ONE. 2, e373 (2007).</li><li>Bhatia, S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+host+defense+against+Aspergillus+fumigatus+involves+alveolar+macrophages+with+a+predominance+ofalternatively+activated+phenotype.">Rapid host defense against Aspergillus fumigatus involves alveolar macrophages with a predominance ofalternatively activated phenotype.</a> PLoS One. 6, e15943 (2011).</li><li>Raes, G., Noel, W., Beschin, A., Brys, L., de Baetselier, P., Hassanzadeh, G. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=FIZZ1+and+Ym+as+tools+to+discriminate+between+differentially+activated+macrophages.">FIZZ1 and Ym as tools to discriminate between differentially activated macrophages.</a> Dev. Immunol. 9, 151-159 (2002).</li><li>Gesuete, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recombinant+C1+inhibitor+in+brain+ischemic+injury.">Recombinant C1 inhibitor in brain ischemic injury.</a> Ann. Neurol. 66, 332-342 (2009).</li><li>Sica, A., Mantovani, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Macrophages+plasticity+and+polarization:+in+vivo+veritas.">Macrophages plasticity and polarization: in vivo veritas.</a> J. Clin. Invest. 122 (3), 787-795 (2012).</li></ol>

We present here immunofluorescence-based protocols followed by three-dimensional confocal analysis as a powerful approach to investigate localization and co-expression of M/M phenotype markers into the ischemic area (for a more detailed analysis see ref 6). This method combines specific staining of relevant marker of M/M activation with three-dimensional confocal imaging. The fine tuning of antibodies, serum and fluorconjugated working dilutions allows optimal signal to noise ratio of the investigated m...

After acute brain injury, microglia are rapidly activated and undergo dramatic morphological and phenotypic changes1-3. This intrinsic response is associated to recruitment of blood-born macrophages which migrate into the injured brain parenchyma4,5. The role of microglia and macrophages which are antigenically not distinguishable (henceforth referred to as M/M) in brain injury is still debated. An increasing number of studies indicate that, similarly to what described for peripheral macrophages, microglia and brain recruited macrophages can assume different phenotypes whose extremes correspond to classic pro-inflammatory toxic (M1) or anti-inflammatory protective (M2) phenotype. The different activation states, including secretion of pro- or anti-inflammatory factors, release of neurotrophic molecules and lysosomal activity are characterized by a specific pattern of phenotypic markers, whose expression depends on the temporal evolution of the surrounding environment. The characterization of these M/M phenotypes in the injured brain is still scanty. We used a well-established murine model of pMCAo to analyze M/M expression and evolution after stroke. Immunofluorescence based protocols presented here aim at getting insight into the appearance of specific M/M phenotype markers, their localization and cellular co-expression in the ischemic area. We investigated a few molecules associated to different activation state or phenotype, namely CD11b, a surface marker expressed by leukocytes and a widely used marker of M/M activation/recruitment6-8, CD68 a marker of lysosomes6,7 and Ym1 a secretory protein expressed by alternatively activated (M2) macrophages and associated to recovery and function restoration9-10.	
	When two markers are expressed by the same cell, but in different subcellular compartments, colocalization alone may not be much informative. In this case, analysis of coexpression can be performed by using single plane view and by three-dimensional renderings. We here describe a protocol to obtain a thorough three-dimensional analysis of marker coexpression.

<table border="1">
		<tbody>
		 <tr>
			<td></td>
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			<td></td>
			<td>Materials</td>
		 </tr>
		 <tr>
			<td>Rat Anti-mouse CD11b</td>
			<td>Kindly provided by Dr. A. Doni, Istituto Clinico Humanitas, Milan, Italy</td>
			<td></td>
			<td></td>
		 </tr>
		 <tr>
			<td>Rat Anti-mouse CD68 </td>
			<td>AbD Serotec</td>
			<td>MCA 1957</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Rabbit Anti-mouse Ym1 </td>
			<td>Stem Cell Technologies</td>
			<td>1404</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Hoechst 33342</td>
			<td>Life technologies</td>
			<td>H21492</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Mouse Anti-Neural Nuclei (NeuN)</td>
			<td>CHEMICON</td>
			<td>MAB377</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Biotinilated Goat Anti-Rat antibody</td>
			<td>Jackson Immuno Research</td>
			<td>112-065-143</td>
			<td></td>
		 </tr>
		 <tr>
			<td>TSA Cyanine 5 System </td>
			<td>Perkin Elmer</td>
			<td>NEL705A001KT</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Prolong Gold </td>
			<td>Invitrogen</td>
			<td>P36930</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Anti-rat alexa 546</td>
			<td>Invitrogen</td>
			<td>A-11081</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Anti mouse Alexa 488</td>
			<td>Invitrogen</td>
			<td>A-21121</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Anti-rabbit Alexa 594</td>
			<td>Invitrogen</td>
			<td>A-11037</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Normal Goat Serum</td>
			<td>Vectors Laboratories</td>
			<td>S-1000</td>
			<td></td>
		 </tr>
		 <tr>
			<td>Tritin X-100</td>
			<td>Sigma</td>
			<td>T8787</td>
			<td></td>
		 </tr>
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			<td>Phosphate Buffered Saline</td>
			<td>Sigma</td>
			<td>P4417-100</td>
			<td></td>
		 </tr>
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			<td></td>
			<td></td>
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			<td>Equipment</td>
		 </tr>
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			<td>Cryostat CM1850</td>
			<td>Leica</td>
			<td></td>
			<td></td>
		 </tr>
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			<td>Olympus IX81 confocal microscope </td>
			<td>Olympus</td>
			<td></td>
			<td></td>
		 </tr>
		 <tr>
			<td>AnalySIS software</td>
			<td>Olympus</td>
			<td></td>
			<td></td>
		 </tr>
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			<td>Imaris software 5.0</td>
			<td>Bitplane</td>
			<td></td>
			<td></td>
		 </tr>
		 <tr>
			<td>Photoshop cs2</td>
			<td>Adobe Systems</td>
			<td></td>
			<td></td>
		 </tr>
		 <tr>
			<td>Software packages GraphPad Prism version 4.0</td>
			<td>GraphPad Software Inc.</td>
			<td></td>
			<td></td>
		 </tr>
		</tbody>
 </table>

three-dimensional confocal analysis of microglia/macrophage markers of polarization in experimental brain injury

After brain stroke microglia/macrophages (M/M) undergo rapid activation with dramatic morphological and phenotypic changes that include expression of novel surface antigens and production of mediators that build up and maintain the inflammatory response. Emerging evidence indicates that M/M are highly plastic cells that can assume classic pro-inflammatory (M1) or alternative anti-inflammatory (M2) activation after acute brain injury. However a complete characterization of M/M phenotype marker expression, their colocalization and temporal evolution in the injured brain is still missing.	
	Immunofluorescence protocols specifically staining relevant markers of M/M activation can be performed in the ischemic brain. Here we present immunofluorescence-based protocols followed by three-dimensional confocal analysis as a powerful approach to investigate the pattern of localization and co-expression of M/M phenotype markers such as CD11b, CD68, Ym1, in mouse model of focal ischemia induced by permanent occlusion of the middle cerebral artery (pMCAO). Two-dimensional analysis of the stained area reveals that each marker is associated to a defined M/M morphology and has a given localization in the ischemic lesion. Patterns of M/M phenotype marker co-expression can be assessed by three-dimensional confocal imaging in the ischemic area. Images can be acquired over a defined volume (10 &mu;m z-axis and a 0.23 &mu;m step size, corresponding to a 180 x 135 x 10 &mu;m volume) with a sequential scanning mode to minimize bleed-through effects and avoid wavelength overlapping. Images are then processed to obtain three-dimensional renderings by means of Imaris software. Solid view of three dimensional renderings allows the definition of marker expression in clusters of cells. We show that M/M have the ability to differentiate towards a multitude of phenotypes, depending on the location in the lesion site and time after injury.

An example of the results obtained when labeling protocols and confocal acquisitions are carried out into the ischemic region is illustrated in Figures 1A and 1B. A two dimensional view of acquired images shows that at twenty-four hours after ischemia (A), the lysosomal marker CD68 (green) is expressed in hypertrophic ameboid CD11b cells (red) present in the ischemic core. In the border zone (B) CD11b positive cells display round cell bodies and ramified...

Watch this Scientific Journal Video about Three-dimensional Confocal Analysis of Microglia/macrophage Markers of Polarization in Experimental Brain Injury at JoVE.com

Three-dimensional Confocal Analysis of Microglia/macrophage Markers of Polarization in Experimental Brain Injury

A way to gain new insights into the complexity of the brain inflammatory response is presented. We describe immunofluorescence-based protocols followed by three-dimensional confocal analysis to investigate the pattern of co-expression of microglia/macrophage phenotype markers in a mouse model of focal ischemia.

After brain stroke microglia/macrophages (M/M) undergo  rapid activation with dramatic morphological and phenotypic changes that  include expression of ...

three-dimensional-confocal-analysis-microgliamacrophage-markers

Research

JoVE Journal

Neuroscience

Visualization and Genetic Manipulation of Dendrites and Spines in the Mouse Cerebral Cortex and Hippocampus using In utero Electroporation

In utero electroporation (IUE) has become a powerful technique to study the development of different regions of the embryonic nervous system 1-5. To date this tool has been widely used to study the regulation of cellular proliferation, differentiation and neuronal migration especially in the developing cerebral cortex 6-8. Here we detail our protocol to electroporate in utero the cerebral cortex and the hippocampus and provide evidence that this approach can be used to study dendrites and spines in these two cerebral regions.
Visualization and manipulation of neurons in primary cultures have contributed to a better understanding of the processes involved in dendrite, spine and synapse development. However neurons growing in vitro are not exposed to all the physiological cues that can affect dendrite and/or spine formation and maintenance during normal development. Our knowledge of dendrite and spine structures in vivo in wild-type or mutant mice comes mostly from observations using the Golgi-Cox method 9. However, Golgi staining is considered to be unpredictable. Indeed, groups of nerve cells and fiber tracts are labeled randomly, with particular areas often appearing completely stained while adjacent areas are devoid of staining. Recent studies have shown that IUE of fluorescent constructs represents an attractive alternative method to study dendrites, spines as well as synapses in mutant / wild-type mice 10-11 (Figure 1A). Moreover in comparison to the generation of mouse knockouts, IUE represents a rapid approach to perform gain and loss of function studies in specific population of cells during a specific time window. In addition, IUE has been successfully used with inducible gene expression or inducible RNAi approaches to refine the temporal control over the expression of a gene or shRNA 12. These advantages of IUE have thus opened new dimensions to study the effect of gene expression/suppression on dendrites and spines not only in specific cerebral structures (Figure 1B) but also at a specific time point of development (Figure 1C).
Finally, IUE provides a useful tool to identify functional interactions between genes involved in dendrite, spine and/or synapse development. Indeed, in contrast to other gene transfer methods such as virus, it is straightforward to combine multiple RNAi or transgenes in the same population of cells. 
In summary, IUE is a powerful method that has already contributed to the characterization of molecular mechanisms underlying brain function and disease and it should also be useful in the study of dendrites and spines.

Visualization and Genetic Manipulation of Dendrites and Spines in the Mouse Cerebral Cortex and Hippocampus using In utero Electroporation

This article describes in detail a protocol to electroporate in utero the cerebral cortex and the hippocampus at E14.5 in mice. We also show that this is a valuable method to study dendrites and spines in these two cerebral regions.

In utero electroporation (IUE) has become a powerful technique to study the development of different regions of the embryonic nervous system 1-5. To date ...

Protocol for Three-dimensional Confocal Morphometric Analysis of Astrocytes

As glial cells in the brain, astrocytes have diverse functional roles in the central nervous system. In the presence of harmful stimuli, astrocytes modify their functional and structural properties, a condition called reactive astrogliosis. Here, a protocol for assessment of the morphological properties of astrocytes is presented. This protocol includes quantification of 12 different parameters i.e. the surface area and volume of the tissue covered by an astrocyte (astrocyte territory), the entire astrocyte including branches, cell body, and nucleus, as well as total length and number of branches, the intensity of fluorescence immunoreactivity of antibodies used for astrocyte detection, and astrocyte density (number/1,000 &#181;m2). For this purpose three-dimensional (3D) confocal microscopic images were created, and 3D image analysis software such as Volocity 6.3 was used for measurements. Rat brain tissue exposed to amyloid beta1-40 (A&#946;1-40) with or without a therapeutic&#160;intervention was used to present the method. This protocol can also be used for 3D morphometric analysis of other cells from either in vivo or in vitro conditions.

Astrocytes in the CNS change their functional and structural properties in response to harmful stimuli. This report presents a protocol for assessment of three-dimensional astrocyte morphology in diseased conditions or after therapeutic interventions.

As glial cells in the brain, astrocytes have diverse functional roles in the central nervous system. In the presence of harmful stimuli, astrocytes modify ...

Three-dimensional Imaging and Analysis of Mitochondria within Human Intraepidermal Nerve Fibers

The goal of this protocol is to study mitochondria within intraepidermal nerve fibers. Therefore, 3D imaging and analysis techniques were developed to isolate nerve-specific mitochondria and evaluate disease-induced alterations of mitochondria in the distal tip of sensory nerves. The protocol combines fluorescence immunohistochemistry, confocal microscopy and 3D image analysis techniques to visualize and quantify nerve-specific mitochondria. Detailed parameters are defined throughout the procedures in order to provide a concrete example of how to use these techniques to isolate nerve-specific mitochondria. Antibodies were used to label nerve and mitochondrial signals within tissue sections of skin punch biopsies, which was followed by indirect immunofluorescence to visualize nerves and mitochondria with a green and red fluorescent signal respectively. Z-series images were acquired with confocal microscopy and 3D analysis software was used to process and analyze the signals. It is not necessary to follow the exact parameters described within, but it is important to be consistent with the ones chosen throughout the staining, acquisition and analysis steps. The strength of this protocol is that it is applicable to a wide variety of circumstances where one fluorescent signal is used to isolate other signals that would otherwise be impossible to study alone.

This protocol uses three-dimensional (3D) imaging and analysis techniques to visualize and quantify nerve-specific mitochondria. The techniques are applicable to other situations where one fluorescent signal is used to isolate a subset of data from another fluorescent signal.

The goal of this protocol is to study mitochondria within intraepidermal nerve fibers. Therefore, 3D imaging and analysis techniques were developed to ...

Anatomically Inspired Three-dimensional Micro-tissue Engineered Neural Networks for Nervous System Reconstruction, Modulation, and Modeling

Functional recovery rarely occurs&#160;following injury or disease-induced degeneration within the central nervous system (CNS)&#160;due to the inhibitory environment and the limited capacity for neurogenesis. We are developing&#160;a strategy to simultaneously address&#160;neuronal and axonal pathway loss within the damaged CNS. This manuscript presents the fabrication protocol for micro-tissue engineered neural networks (micro-TENNs), implantable constructs consisting of neurons and aligned axonal tracts spanning the extracellular matrix (ECM) lumen of a preformed hydrogel cylinder hundreds of microns in diameter that may extend centimeters in length. Neuronal aggregates are delimited to the extremes of the three-dimensional encasement and are spanned by axonal projections. Micro-TENNs are uniquely poised as a strategy for CNS reconstruction, emulating aspects of brain connectome cytoarchitecture and potentially providing means for network replacement. The neuronal aggregates may synapse with host tissue to form new functional relays to restore and/or modulate missing or damaged circuitry. These constructs may also act as pro-regenerative&#160;&#34;living scaffolds&#34; capable of exploiting developmental mechanisms for cell migration and axonal pathfinding, providing synergistic structural and soluble cues based on the state of regeneration. Micro-TENNs are fabricated by pouring liquid hydrogel into a cylindrical mold containing a longitudinally centered needle. Once the hydrogel has gelled, the needle is removed, leaving a hollow micro-column. An ECM solution is added to the lumen to provide an environment suitable for neuronal adhesion and axonal outgrowth. Dissociated neurons are mechanically aggregated for precise seeding within one or both ends of the micro-column. This methodology reliably produces self-contained miniature constructs with long-projecting axonal tracts that may recapitulate features of brain neuroanatomy. Synaptic immunolabeling and genetically encoded calcium indicators suggest that micro-TENNs possess extensive synaptic distribution and intrinsic electrical activity. Consequently, micro-TENNs represent a promising strategy for targeted neurosurgical reconstruction of brain pathways and may also be applied as biofidelic models to study neurobiological phenomena in vitro.

This manuscript details the fabrication of micro-tissue engineered neural networks: three-dimensional micron-sized constructs comprised of long aligned axonal tracts spanning aggregated neuronal population(s) encased in a tubular hydrogel. These living scaffolds can serve as functional relays to reconstruct or modulate neural circuitry or as biofidelic test-beds mimicking gray-white matter neuroanatomy.

Functional recovery rarely occurs&#160;following injury or disease-induced degeneration within the central nervous system (CNS)&#160;due to the inhibitory ...

Automated Gait Analysis in Mice with Chronic Constriction Injury

The von Frey test is a classical method that has been widely used to examine the sensory function of neuropathic pain animals. However, it has some disadvantages such as subjective data and the requirement of a skilled, experienced experimenter. To date, a variety of modifications have improved the von Frey method, but it still has a few limitations. Recent reports have suggested that gait analysis produces more accurate and objective data from the neuropathic animals. This protocol demonstrates how to perform the automated gait analysis to determine the degree of neuropathic pain in mice. After several days of acclimation, the mice were allowed to walk freely on the glass floor to illuminate footprints. Then, quantification of the footprints and gait were performed through video clips with automatic analysis of various walking parameters, such as area of paw print, swing time, angle of paw, etc.
The main purpose of this study is to describe the methodology of automated gait analysis and briefly compare it with data from the classical sensory test using von Frey filament.

The precise assessment of pain response in a neuropathic animal model is critical to investigate the pathophysiology of pain diseases and develop new analgesics. We present a sensitive and objective method to determine the sensory function of the rodent hind paw by an automated gait analysis system.

The von Frey test is a classical method that has been widely used to examine the sensory function of neuropathic pain animals. However, it has some ...

Large-scale Three-dimensional Imaging of Cellular Organization in the Mouse Neocortex

The mammalian neocortex is composed of many types of excitatory and inhibitory neurons, each with specific electrophysiological and biochemical properties, synaptic connections, and in vivo functions, but their basic functional and anatomical organization from cellular to network scale is poorly understood. Here we describe a method for the three-dimensional imaging of fluorescently-labeled neurons across large areas of the brain for the investigation of the cortical cellular organization. Specific types of neurons are labeled by the injection of fluorescent retrograde neuronal tracers or expression of fluorescent proteins in transgenic mice. Block brain samples, e.g., a hemisphere, are prepared after fixation, made transparent with tissue clearing methods, and subjected to fluorescent immunolabeling of the specific cell types. Large areas are scanned using confocal or two-photon microscopes equipped with large working distance objectives and motorized stages. This method can resolve the periodic organization of the cell type-specific microcolumn functional modules in the mouse neocortex. The procedure can be useful for the study of three-dimensional cellular architecture in the diverse brain areas and other complex tissues.

Here we describe a procedure for tissue clearing, fluorescent labeling, and large-scale imaging of mouse brain tissue which, thereby, enables visualization of the three-dimensional organization of cell types in the neocortex.

The mammalian neocortex is composed of many types of excitatory and inhibitory neurons, each with specific electrophysiological and biochemical ...

Chronic Implantation of Whole-cortical Electrocorticographic Array in the Common Marmoset

Electrocorticography (ECoG) allows the monitoring of electrical field potentials from the cerebral cortex with high spatiotemporal resolution. Recent development of thin, flexible ECoG electrodes has enabled conduction of stable recordings of large-scale cortical activity. We have developed a whole-cortical ECoG array for the common marmoset. The array continuously covers almost the entire lateral surface of cortical hemisphere, from the occipital pole to the temporal and frontal poles, and it captures whole-cortical neural activity in one shot. This protocol describes a chronic implantation procedure of the array in the epidural space of the marmoset brain. Marmosets have two advantages regarding ECoG recordings, one being the homologous organization of anatomical structures in humans and macaques, including frontal, parietal, and temporal complexes. The other advantage is that the marmoset brain is lissencephalic and contains a large number of complexes, which are more difficult to access in macaques with ECoG, that are exposed to the brain surface.These features allow direct access to most cortical areas beneath the surface of the brain. This system provides an opportunity to investigate global cortical information processing with high resolutions at a sub-millisecond order in time and millimeter order in space.

We have developed a whole-cortical electrocorticographic array for the common marmoset that continuously covers almost the entire lateral surface of cortex, from the occipital pole to the temporal and frontal poles. This protocol describes a chronic implantation procedure of the array in the epidural space of the marmoset brain.

Electrocorticography (ECoG) allows the monitoring of electrical field potentials from the cerebral cortex with high spatiotemporal resolution. Recent ...

Three-Dimensional Shape Modeling and Analysis of Brain Structures

Statistical shape analysis of brain structures has been used to investigate the association between their structural changes and pathological processes. We have developed a software package for accurate and robust shape modeling and group-wise analysis. Here, we introduce an pipeline for the shape analysis, from individual 3D shape modeling to quantitative group shape analysis. We also describe the pre-processing and segmentation steps using open software packages. This practical guide would help researchers save time and effort in 3D shape analysis on brain structures.

We introduce a semi-automatic protocol for shape analysis on brain structures, including image segmentation using open software, and further group-wise shape analysis using an automated modeling package. Here, we demonstrate each step of the 3D shape analysis protocol with hippocampal segmentation from brain MR images.

Statistical shape analysis of brain structures has been used to investigate the association between their structural changes and pathological processes. ...

Systems Analysis of the Neuroinflammatory and Hemodynamic Response to Traumatic Brain Injury

Mild traumatic brain injuries (mTBIs) are a significant public health problem. Repeated exposure to mTBI can lead to cumulative, long-lasting functional deficits. Numerous studies by our group and others have shown that mTBI stimulates cytokine expression and activates microglia, decreases cerebral blood flow and metabolism, and impairs cerebrovascular reactivity. Moreover, several works have reported an association between derangements in these neuroinflammatory and hemodynamic markers and cognitive impairments. Herein we detail methods to characterize the neuroinflammatory and hemodynamic tissue response to mTBI in mice. Specifically, we describe how to perform a weight-drop model of mTBI, how to longitudinally measure cerebral blood flow using a non-invasive optical technique called diffuse correlation spectroscopy, and how to perform a Luminex multiplexed immunoassay on brain tissue samples to quantify cytokines and immunomodulatory phospho-proteins (e.g., within the MAPK and NF&#954;B pathways) that respond to and regulate activity of microglia and other neural immune cells. Finally, we detail how to integrate these data using a multivariate systems analysis approach to understand the relationships between all of these variables. Understanding the relationships between these physiologic and molecular variables will ultimately enable us to identify mechanisms responsible for mTBI.

This protocol presents methods to characterize the neuroinflammatory and hemodynamic response to mild traumatic brain injury and to integrate these data as part of a multivariate systems analysis using partial least squares regression.

Mild traumatic brain injuries (mTBIs) are a significant public health problem. Repeated exposure to mTBI can lead to cumulative, long-lasting functional ...

Three-Dimensional Motor Nerve Organoid Generation

A fascicle of axons is one of the major structural motifs observed in the nervous system. Disruption of axon fascicles could cause developmental and neurodegenerative diseases. Although numerous studies of axons have been conducted, our understanding of formation and dysfunction of axon fascicles is still limited due to the lack of robust three-dimensional in vitro models. Here, we describe a step-by-step protocol for the rapid generation of a motor nerve organoid (MNO) from human induced pluripotent stem (iPS) cells in a microfluidic-based tissue culture chip. First, fabrication of chips used for the method is described. From human iPS cells, a motor neuron spheroid (MNS) is formed. Next, the differentiated MNS is transferred into the chip. Thereafter, axons spontaneously grow out of the spheroid and assemble into a fascicle within a microchannel equipped in the chip, which generates an MNO tissue carrying a bundle of axons extended from the spheroid. For the downstream analysis, MNOs can be taken out of the chip to be fixed for morphological analyses or dissected for biochemical analyses, as well as calcium imaging and multi-electrode array recordings. MNOs generated with this protocol can facilitate drug testing and screening and can contribute to understanding of mechanisms underlying development and diseases of axon fascicles.

This protocol provides a comprehensive procedure to fabricate human iPS cell-derived motor nerve organoid through spontaneous assembly of a robust bundle of axons extended from a spheroid in a tissue culture chip.

A fascicle of axons is one of the major structural motifs observed in the nervous system. Disruption of axon fascicles could cause developmental and ...