Name: quantitative 3d in silico modeling (q3dism) of cerebral amyloid-beta phagocytosis in rodent models of alzheimer's disease
Uploaded: 2016-12-26T13:00:00
Description: Watch this Scientific Journal Video about Quantitative 3D In Silico Modeling q3DISM of Cerebral Amyloid-beta Phagocytosis in Rodent Models of Alzheimer's Disease at JoVE.com

M-V.G-S. is supported by a BrightFocus Foundation Alzheimer's Disease Research Fellowship Award (A2015309F) and an Alzheimer's Association, California Southland Chapter Young Investigator Award. T.M.W. is supported by an ARCS Foundation and John Douglas French Alzheimer's Foundation Maggie McKnight Russell-JDFAF Memorial Postdoctoral Fellowship. This work was supported by the National Institute on Neurologic Disorders and Stroke (1R01NS076794-01, to T.T.), an Alzheimer's Association Zenith Fellows Award (ZEN-10-174633, to T.T.), and an American Federation of Aging Research/Ellison Medical Foundation Julie Martin Mid-Career Award in Aging Research (M11472, to T.T.). We are grateful for startup funds from the Zilkha Neurogenetic Institute, which helped to make this work possible. &#8195;

Statement of research ethics: All experiments involving animals detailed herein were approved by the University of Southern California Institutional Animal Care and Use Committee (IACUC) and performed in strict accordance with National Institutes of Health guidelines and recommendations from the Association for Assessment and Accreditation of Laboratory Animal Care International.
1. Rodent Brain Isolation and Preparation for Immunostaining
DAY 1:
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	<li>Place aged TgF344-AD rats (14-mo...

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The protocol that we describe in this report for true 3D quantitation of A&#946; phagocytosis in vivo by mononuclear phagocytes relies on specific labeling of cellular and subcellular compartments as well as A&#946; deposits. Specifically, we use Iba1 (Ionized-calcium Binding Adaptor molecule 1), a protein that is involved in membrane ruffling and phagocytosis upon cell activation18,19, to stain cerebral mononuclear phagocytes. While Iba1+ cells are generally regarded ...

Alzheimer&#39;s Disease (AD), the most common age-related dementia1, is characterized by cerebral amyloid-&#946; (A&#946;) accumulation as &#34;senile&#34; &#946;-amyloid plaques, chronic low-level neuroinflammation, tauopathy, neuronal loss, and cognitive disturbance2. In AD patient brains, neuroinflammation is earmarked by reactive astrocytes and mononuclear phagocytes (referred to as microglia, although their central vs. peripheral origin remains unclear) surrounding A&#946; deposits3. As the innate immune sentinels of the CNS, microglia are centrally positioned to clear brain A&#946;. However, microglial recruitment to A&#946; plaques is accompanied by very little, if any, A&#946; phagocytosis4,5. One hypothesis is that microglia are initially neuroprotective by phagocytozing small assemblies of A&#946;. However, eventually these cells become neurotoxic as overwhelming A&#946; burden and/or age-related functional decline, provokes microglia into a dysfunctional proinflammatory phenotype, contributing to neurotoxicity and cognitive decline6.
Recent Genome-wide Association Studies (GWAS) have identified a cluster of AD risk alleles belonging to core innate immune pathways7 that modulate phagocytosis8-11. Consequently, the immune response to cerebral amyloid deposition has become a major area of interest, both in terms of understanding AD etiology and for developing new therapeutic approaches12-14. Yet, there is a vital need for methodology to evaluate A&#946; phagocytosis in vivo. To address this unmet need, we have developed quantitative 3D in silico modeling (q3DISM) to enable true 3D quantitation of cerebral A&#946; phagocytosis by mononuclear phagocytes in rodent models of Alzheimer-like disease.
Limited only by the extent to which they recapitulate disease, animal models have proven invaluable for understanding AD pathoetiology and for evaluating experimental therapeutics. Owing to the fact that mutations in the Presenilin&#160;(PS) and Amyloid Precursor Protein (APP) genes independently cause autosomal dominant AD, these mutant transgenes have been extensively used to generate transgenic rodent models. Transgenic APP/PS1 mice simultaneously coexpressing &#34;Swedish&#34; mutant human APP (APPswe) and &#916; exon 9 mutant human presenilin 1 (PS1&#916;E9) present with accelerated cerebral amyloidosis and neuroinflammation15,16. Further, we have generated bi-transgenic rats coinjected with APPswe and PS1&#916;E9 constructs (line TgF344-AD, on a Fischer 344 background). Unlike transgenic mouse models of cerebral amyloidosis, TgF344-AD rats develop cerebral amyloid that precedes tauopathy, apoptotic loss of neurons, and behavioral impairment17.
In this report, we describe a protocol for immunostaining microglia, phagolysosomes and A&#946; deposits in brain sections from APP/PS1 mice and TgF344-AD rats, and acquisition of large z-dimensional confocal images. We detail in silico generation and analysis of true 3D reconstructions from confocal datasets allowing quantitation of A&#946; uptake into microglial phagolysosomes. More broadly, the methodology that we detail here can be used to quantify virtually any form of phagocytosis in vivo.

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			<td height="40" style="height:40px;width:384px;">Isoflurane</td>
			<td style="width:152px;">Abbott</td>
			<td style="width:127px;">NDC 0044-5260-05</td>
			<td style="width:249px;"></td>
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			<td height="20" style="height:20px;width:384px;">Dissecting scissors</td>
			<td style="width:152px;">VWR</td>
			<td style="width:127px;">82027-582</td>
			<td></td>
		</tr>
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			<td height="20" style="height:20px;width:384px;">Dissecting scissors Blunt tip</td>
			<td style="width:152px;">VWR</td>
			<td style="width:127px;">82027-588</td>
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			<td height="20" style="height:20px;width:384px;">Tweezers</td>
			<td style="width:152px;">VWR</td>
			<td>94024-408</td>
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			<td height="20" style="height:20px;width:384px;">23G needle</td>
			<td style="width:152px;">VWR</td>
			<td>BD305145</td>
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			<td height="20" style="height:20px;width:384px;">peristaltic pump FH10</td>
			<td style="width:152px;">Thermo Scientific</td>
			<td>72-310-010</td>
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			<td height="20" style="height:20px;width:384px;">PBS 10X</td>
			<td style="width:152px;">Bioland Scientific</td>
			<td style="width:127px;">PBS01-02</td>
			<td>Working concentration 1X</td>
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			<td height="20" style="height:20px;width:384px;">Adult Mouse Brain Matrix, Coronal slices, Stainless Steel 1mm&#160;</td>
			<td style="width:152px;">Kent Scientific</td>
			<td>RBMS-200C</td>
			<td></td>
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			<td height="20" style="height:20px;width:384px;">Adult Rat Brain Matrix, Coronal slices, Stainless Steel 1mm&#160;</td>
			<td style="width:152px;">Kent Scientific</td>
			<td>RBMS-305C&#160;</td>
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			<td height="20" style="height:20px;width:384px;">32% Paraformaldehyde aqueous solution</td>
			<td style="width:152px;">EMS</td>
			<td style="width:127px;">15714-S</td>
			<td>Caution: Toxic. Working concentration 4% in PBS</td>
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			<td height="20" style="height:20px;width:384px;">Ethanol</td>
			<td style="width:152px;">VWR</td>
			<td>89125-188</td>
			<td>Various concentrations, see protocol</td>
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			<td height="20" style="height:20px;width:384px;">Tissue-Tek Uni-cassettes Sakura</td>
			<td style="width:152px;">VWR</td>
			<td>25608-774</td>
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			<td height="20" style="height:20px;width:384px;">Embedding and Infiltration Paraffin</td>
			<td style="width:152px;">VWR</td>
			<td>15147-839</td>
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			<td height="20" style="height:20px;width:384px;">Microtome Leica RM2125</td>
			<td style="width:152px;">Leica Biosystems</td>
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			<td height="20" style="height:20px;width:384px;">Disposable Microtome Blades&#160;</td>
			<td style="width:152px;">VWR</td>
			<td style="width:127px;">25608-964</td>
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			<td height="20" style="height:20px;width:384px;">Water bath Leica HI 1210</td>
			<td style="width:152px;">Leica Biosystems</td>
			<td style="width:127px;"></td>
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			<td height="20" style="height:20px;width:384px;">Micro slide Superfrost plus</td>
			<td style="width:152px;">VWR</td>
			<td style="width:127px;">48311-703</td>
			<td></td>
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			<td height="20" style="height:20px;width:384px;">Xylene</td>
			<td style="width:152px;">Sigma-Aldrich</td>
			<td style="width:127px;">534056-4X4L</td>
			<td style="width:249px;">Caution: Toxic&#160;</td>
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			<td height="20" style="height:20px;width:384px;">Target Retrieval Solution 10X</td>
			<td style="width:152px;">DAKO</td>
			<td style="width:127px;">S1699</td>
			<td>Working concentration 1X</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">KimWipes</td>
			<td style="width:152px;">VWR</td>
			<td>21905-026</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:384px;">Hydrophobic PAP pen</td>
			<td style="width:152px;">VWR</td>
			<td style="width:127px;">95025-252</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:384px;">Triton X-100</td>
			<td style="width:152px;">VWR</td>
			<td style="width:127px;">97062-208</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:384px;">Normal Donkey Serum</td>
			<td style="width:152px;">Jackson Immuno</td>
			<td style="width:127px;">017-000-121</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:384px;">Coverslips</td>
			<td style="width:152px;">VWR</td>
			<td style="width:127px;">48393081</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:384px;">Prolong Gold antifade reagent with DAPI</td>
			<td style="width:152px;">Life Technologies</td>
			<td style="width:127px;">P36935</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:384px;">Glass Slide Rack</td>
			<td style="width:152px;">VWR</td>
			<td style="width:127px;">100492-942</td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:384px;">Iba1 antibody (polyclonal, rabbit)</td>
			<td style="width:152px;">Wako</td>
			<td style="width:127px;">019-19741&#160;</td>
			<td>Working concentration 1:200</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:384px;">Iba1 antibody (polyclonal, goat)</td>
			<td style="width:152px;">LifeSpan Bioscience</td>
			<td style="width:127px;">LS-B2645</td>
			<td>Working concentration 1:200</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:384px;">rat CD68 [KP1] antibody (monoclonal, mouse)</td>
			<td style="width:152px;">Abcam</td>
			<td style="width:127px;">ab955</td>
			<td>Working concentration 1:200</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:384px;">mouse CD68 [FA-11] antibody (monoclonal, rat)</td>
			<td style="width:152px;">Abcam</td>
			<td style="width:127px;">ab53444</td>
			<td>Working concentration 1:200</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:384px;">mouse CD107a (LAMP1) antibody (monoclonal, rat)</td>
			<td style="width:152px;">Affymetrix</td>
			<td style="width:127px;">14-1071</td>
			<td>Working concentration 1:100</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:384px;">Beta-Amyloid, 17-24 (4G8) antibody (monoclonal, mouse)</td>
			<td style="width:152px;">Covance</td>
			<td style="width:127px;">SIG-39220</td>
			<td>Working concentration 1:200</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:384px;">Beta-Amyloid, 1-16 (6E10) antibody (monoclonal, mouse)</td>
			<td style="width:152px;">Covance</td>
			<td style="width:127px;">SIG-39320</td>
			<td>Working concentration 1:200</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:384px;">OC antibody (polyclonal, rabbit)</td>
			<td colspan="2">Gifted by D. H. Cribbs and C. G. Glabe (UC Irvine)</td>
			<td>Working concentration 1:200</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:384px;">Alexa Fluor 488&#160; mouse secondary antibody</td>
			<td style="width:152px;">Invitrogen</td>
			<td style="width:127px;">A-11001</td>
			<td>Working concentration 1:1000</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:384px;">Alexa Fluor 488&#160; rat secondary antibody</td>
			<td style="width:152px;">Invitrogen</td>
			<td>A-11006</td>
			<td>Working concentration 1:1000</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:384px;">Alexa Fluor 594 rabbit secondary antibody</td>
			<td style="width:152px;">Invitrogen</td>
			<td>A-11037</td>
			<td>Working concentration 1:1000</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:384px;">Alexa Fluor 594 goat secondary antibody</td>
			<td style="width:152px;">Invitrogen</td>
			<td>A-11080</td>
			<td>Working concentration 1:1000</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:384px;">Alexa Fluor 647 mouse secondary antibody</td>
			<td style="width:152px;">Invitrogen</td>
			<td>A-21235</td>
			<td>Working concentration 1:1000</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:384px;">Alexa Fluor 647 rabbit secondary antibody</td>
			<td style="width:152px;">Invitrogen</td>
			<td>A-21443</td>
			<td>Working concentration 1:1000</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:384px;">Immersion oil</td>
			<td style="width:152px;">Nikon&#160;</td>
			<td style="width:127px;"></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:384px;">A1 Confocal microscope</td>
			<td style="width:152px;">Nikon&#160;</td>
			<td style="width:127px;"></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:384px;">NIS Elements Advanced Research software</td>
			<td style="width:152px;">Nikon&#160;</td>
			<td style="width:127px;"></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:384px;">Imaris:Bitplane software version 7.6</td>
			<td style="width:152px;">Bitplane</td>
			<td style="width:127px;"></td>
			<td>&#34;coloc&#34; and &#34;supass&#34; modules are used.&#160;Alternatively, the open-source freeware&#160;ImageJ can be used for colocalization&#160;analysis of confocal z-stacks datasets.</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;"></td>
			<td style="width:152px;"></td>
			<td style="width:127px;"></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:384px;"></td>
			<td style="width:152px;"></td>
			<td style="width:127px;"></td>
			<td></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:384px;"></td>
			<td style="width:152px;"></td>
			<td style="width:127px;"></td>
			<td></td>
		</tr>
	</tbody>
</table>

quantitative 3d in silico modeling (q3dism) of cerebral amyloid-beta phagocytosis in rodent models of alzheimer's disease

Neuroinflammation is now recognized as a major etiological factor in neurodegenerative disease. Mononuclear phagocytes are innate immune cells responsible for phagocytosis and clearance of debris and detritus. These cells include CNS-resident macrophages known as microglia, and mononuclear phagocytes infiltrating from the periphery. Light microscopy has generally been used to visualize phagocytosis in rodent or human brain specimens. However, qualitative methods have not provided definitive evidence of in vivo phagocytosis. Here, we describe quantitative 3D in silico modeling (q3DISM), a robust method allowing for true 3D quantitation of amyloid-&#946; (A&#946;) phagocytosis by mononuclear phagocytes in rodent Alzheimer&#39;s Disease (AD) models. The method involves fluorescently visualizing A&#946; encapsulated within phagolysosomes in rodent brain sections. Large z-dimensional confocal datasets are then 3D reconstructed for quantitation of A&#946; spatially colocalized within the phagolysosome. We demonstrate the successful application of q3DISM to mouse and rat brains, but this methodology can be extended to virtually any phagocytic event in any tissue.

Using the multi-stage methodology for q3DISM detailed above, we are able to quantify A&#946; uptake into monocyte phagolysosomes in the brains of APP/PS1 mice (Figure 1) and TgF344-AD rats (Figure 2). Therefore, the q3DISM methodology has enabled analysis of mononuclear phagocytes in mouse and rat models of AD. Interestingly, the volume occupied by CD68+ phagolysosomes is significantly increased in Iba1+ mononuclear phagocytes associ...

Watch this Scientific Journal Video about Quantitative 3D In Silico Modeling q3DISM of Cerebral Amyloid-beta Phagocytosis in Rodent Models of Alzheimer's Disease at JoVE.com

Quantitative 3D In Silico Modeling q3DISM of Cerebral Amyloid-beta Phagocytosis in Rodent Models of Alzheimer&#039;s Disease

We developed a methodology for quantitative 3D in silico modeling (q3DISM) of cerebral amyloid-&#946; (A&#946;) phagocytosis by mononuclear phagocytes in rodent models of Alzheimer&#39;s disease. This method can be generalized for the quantitation of virtually any phagocytic event in vivo.

Quantitative 3D In Silico Modeling (q3DISM) of Cerebral Amyloid-beta Phagocytosis in Rodent Models of Alzheimer's Disease

Neuroinflammation is now recognized as a major etiological factor in neurodegenerative disease. Mononuclear phagocytes are innate immune cells responsible ...

The overall goal of this quantitative 3-D in silico modeling, or q3DISM technique, is to quantify the uptake of amyloid-beta by mononuclear phagocytes in the brains of rodent models of Alzheimer's disease. This method addresses a pressing need in the field of Alzheimer's research for quantifying the clearance of amyloid-beta that is deposited in the brains of Alzheimer's patients forming senile plaques. For the first time, this technique enables true 3-D reconstruction and quantitation of amyloid-beta by macrophages in vivo We began to use cued 3-Dism to study amyloid-beta deposition because we needed a robust tool to visualize and quantify microphage phagocytosis in vivo.This technique may prove useful in testing experimental Alzheimer's disease therapeutics to assess which drugs stimulate macrophages for the efficient clearance of amyloid-beta. When the tissue samples are ready for immunostaining fill the hydrophobic barrier pen-encircled tissue region with blocking buffer for a one hour incubation at room temperature in a humidified chamber. At the end of incubation, replace the blocking buffer with the first primary antibody of interest overnight at 4 degrees Celsius in the humidified chamber.The next morning, wash the samples in three five-minute PBS baths at room temperature with light agitation. After the third wash, incubate the slides with the appropriate fluorescent secondary antibody at room temperature protected from light. After one hour, wash the sections three more times in PBS protected from light.Then label the cells with the other tissue-appropriate primary and secondary antibodies of interest over the next two to four days as just demonstrated. To efficiently stain cellular and supercellular compartments and amyloid-beta deposits, it is crucial to label with only one primary antibody at a time followed by the corresponding secondary antibody. A time-consuming but result-optimizing process.Following the last wash of the secondary antibody staining, allow the sections to dry completely overnight at room temperature in the dark. Then, cover the dried specimens with a cover slip sealed by fluorescent mounting medium containing DAPI. To image the samples by confocal microscopy, select the 60x microscope objective and add immersion oil to the lens.Place the sample onto the microscope stage slide holder and raise the objective until the oil makes contact with the slide. Using epifluorescent illumination, adjust the focal plane to locate the amyloid plaques in the hippocampus or cerebral cortex. Then, acquire confocal images of the activated mononuclear phagocytes surrounding the amyloid deposits in the hippocampus or the cortex.For qualitative 3-D in silico modeling, first analyze the confocal datasets with scientific 3-D image processing in an analysis software colocalization module for spatial proximity of the activated macrophage marker staining in all Z planes simultaneously. Create colocalization channels that correspond to the phagolysosome staining within the activated mononuclear phagocytes. Select TRITC for Channel A, and FITC for Channel B.In the Mode Check window, select Threshold.For the colocalization intensities, select Source Channels. Click Edit to select the colocalization color. Then adjust the thresholds of each channel independently to include the specific staining and to exclude the background and nonspecific signals.The colocalized voxels will appear in the selected colocalization color in all z-stacks simultaneously. Next, click Build Colocalization Channel. The created colocalizaton channel will appear in the Display Adjustment window.Click on the colocalization channel to open the channel statistics. The percentage of volume material A above threshold colocalized represents the monocyte volume occupied by the phagolysosomes. Using the Colocalization Module, analyze the colocalization channel for spatial proximity with the amyloid-beta signals to quantify the amyloid-beta encapsulated within the phagolysosomes.Select the Channel A colocalization data set and Cy5 for Channel B and build a colocalization channel as just demonstrated. Click on the colocalization channel to open the channel statistics again. The percentage of volume material A above threshold colocalized represents the phagolysosomal volume occupied by the amyloid-beta.Using the Surpass Module, reconstruct the confocal image stacks and generate 3-D models of the encapsulated amyloid-beta within the monocyte phagolysosomes. In the Display Adjustment window, select TRITC to show only the macrophage staining, and click add new surface"in the volume properties. Under Settings, in step one of five, algorithm, select Surface.In color, select the color type of interest and adjust the transparency as appropriate. Then check the select region of interest box and click next. In step two of five, region of interest, adjust the X, Y, and Z coordinates to draw a window around the cell of interest and click next.In step three of five, source channel, select the TRITC source channel and check the Smooth box. Set the surface area detail level to 0.4 microns and click next. In step four of five, threshold, adjust the threshold so that the created volume overlaps perfectly with the TRITC channel signal and click next.Finally, in step five of five, classify surfaces, in the Filter Types section, select the objects depending on their size to be included or excluded from the volumes to be created. Repeat the same steps to create 3-D surfaces for phagolysosomes with the FITC channel and amyloid-beta with the Cy5 channel. After qualitative 3-D in silico modeling, as just demonstrated, amyloid-beta uptake into the monocyte phagolysosomes in the brains of transgenic mice and rats can be analyzed.Interestingly, the volume occupied by CD68 positive phagolysosomes is significantly increased in Iba1 positive mononuclear phagocytes, associated with, compared to distant from plaques, in both mice and rats, demonstrating that the mononuclear phagocytes near plaques are poised for phagocytosis, compared to the cells located away from the plaques. It is also noteworthy that plaque-associated mononuclear phagocytes exhibit an increased amyloid-beta uptake in transgenic mice compared to cells distant from plaques whereas in transgenic rats a very modest uptake of amyloid-beta fibrils is observed overall, with no apparent change in amyloid-beta fibril phagocytosis as a function of the distance from the plaques. While attempting this procedure, it's important to remember that the quality of the confocal images is crucial and that similar thresholds should be applied for all channels during the colocalization analysis.Since its development, this technique has paved the way for researchers in the field of neuroinflammation to explore phagocytic events in the brains of rodent models of Alzheimer's disease. After watching this video, you should have a good understanding of how to label rodent brain sections for mononuclear phagocytes, phagolysosome, and amyloid-beta. To quantify the phagocytosis of cerebral amyloid-beta in 3-D in vivo.

quantitative-3d-silico-modeling-q3dism-cerebral-amyloid-beta

Research

JoVE Journal

Medicine

Modeling Stroke in Mice - Middle Cerebral Artery Occlusion with the Filament Model

Stroke is among the most frequent causes of death and adult disability, especially in highly developed countries. However, treatment options to date are very limited. To meet the need for novel therapeutic approaches, experimental stroke research frequently employs rodent models of focal cerebral ischaemia. Most researchers use permanent or transient occlusion of the middle cerebral artery (MCA) in mice or rats.
Proximal occlusion of the middle cerebral artery (MCA) via the intraluminal suture technique (so called filament or suture model) is probably the most frequently used model in experimental stroke research. The intraluminal MCAO model offers the advantage of inducing reproducible transient or permanent ischaemia of the MCA territory in a relatively non-invasive manner. Intraluminal approaches interrupt the blood flow of the entire territory of this artery. Filament occlusion thus arrests flow proximal to the lenticulo-striate arteries, which supply the basal ganglia. Filament occlusion of the MCA results in reproducible lesions in the cortex and striatum and can be either permanent or transient. In contrast, models inducing distal (to the branching of the lenticulo-striate arteries) MCA occlusion typically spare the striatum and primarily involve the neocortex. In addition these models do require craniectomy. In the model demonstrated in this article, a silicon coated filament is introduced into the common carotid artery and advanced along the internal carotid artery into the Circle of Willis, where it blocks the origin of the middle cerebral artery. In patients, occlusions of the middle cerebral artery are among the most common causes of ischaemic stroke. Since varying ischemic intervals can be chosen freely in this model depending on the time point of reperfusion, ischaemic lesions with varying degrees of severity can be produced. Reperfusion by removal of the occluding filament at least partially models the restoration of blood flow after spontaneous or therapeutic (tPA) lysis of a thromboembolic clot in humans.
In this video we will present the basic technique as well as the major pitfalls and confounders which may limit the predictive value of this model.

Filamentous occlusion of the Middle cerebral artery is a common model for studying ischemic stroke in mice.

Stroke is among the most frequent causes of death and adult disability, especially in highly developed countries. However, treatment options to date are ...

Examining the Characteristics of Episodic Memory using Event-related Potentials in Patients with Alzheimer's Disease

Our laboratory uses event-related EEG potentials (ERPs) to understand and support behavioral investigations of episodic memory in patients with amnestic mild cognitive impairment (aMCI) and Alzheimer's disease (AD). Whereas behavioral data inform us about the patients' performance, ERPs allow us to record discrete changes in brain activity. Further, ERPs can give us insight into the onset, duration, and interaction of independent cognitive processes associated with memory retrieval. In patient populations, these types of studies are used to examine which aspects of memory are impaired and which remain relatively intact compared to a control population. The methodology for collecting ERP data from a vulnerable patient population while these participants perform a recognition memory task is reviewed. This protocol includes participant preparation, quality assurance, data acquisition, and data analysis. In addition to basic setup and acquisition, we will also demonstrate localization techniques to obtain greater spatial resolution and source localization using high-density (128 channel) electrode arrays.

Examining the Characteristics of Episodic Memory using Event-related Potentials in Patients with Alzheimer&#039;s Disease

The methodology for collecting high-density event-related potential data while patients with Alzheimer's disease perform a recognition memory task is reviewed. This protocol will include subject preparation, quality assurance, data acquisition, and data analysis.

Our laboratory uses event-related EEG potentials (ERPs) to understand and support behavioral investigations of episodic memory in patients with amnestic ...

Quantitative Analysis of Chromatin Proteomes in Disease

In the nucleus reside the proteomes whose functions are most intimately linked with gene regulation. Adult mammalian cardiomyocyte nuclei are unique due to the high percentage of binucleated cells,1 the predominantly heterochromatic state of the DNA, and the non-dividing nature of the cardiomyocyte which renders adult nuclei in a permanent state of interphase.2 Transcriptional regulation during development and disease have been well studied in this organ,3-5 but what remains relatively unexplored is the role played by the nuclear proteins responsible for DNA packaging and expression, and how these proteins control changes in transcriptional programs that occur during disease.6 In the developed world, heart disease is the number one cause of mortality for both men and women.7 Insight on how nuclear proteins cooperate to regulate the progression of this disease is critical for advancing the current treatment options.
Mass spectrometry is the ideal tool for addressing these questions as it allows for an unbiased annotation of the nuclear proteome and relative quantification for how the abundance of these proteins changes with disease. While there have been several proteomic studies for mammalian nuclear protein complexes,8-13 until recently14 there has been only one study examining the cardiac nuclear proteome, and it considered the entire nucleus, rather than exploring the proteome at the level of nuclear sub compartments.15 In large part, this shortage of work is due to the difficulty of isolating cardiac nuclei. Cardiac nuclei occur within a rigid and dense actin-myosin apparatus to which they are connected via multiple extensions from the endoplasmic reticulum, to the extent that myocyte contraction alters their overall shape.16 Additionally, cardiomyocytes are 40% mitochondria by volume17 which necessitates enrichment of the nucleus apart from the other organelles. Here we describe a protocol for cardiac nuclear enrichment and further fractionation into biologically-relevant compartments. Furthermore, we detail methods for label-free quantitative mass spectrometric dissection of these fractions-techniques amenable to in vivo experimentation in various animal models and organ systems where metabolic labeling is not feasible.

Advances in mass spectrometry have allowed the high throughput analysis of protein expression and modification in a host of tissues. Combined with subcellular fractionation and disease models, quantitative mass spectrometry and bioinformatics can reveal new properties in biological systems. The method described herein analyzes chromatin-associated proteins in the setting of heart disease and is readily applicable to other in vivo models of human disease.

In the nucleus reside the proteomes whose functions are most intimately linked with gene regulation. Adult mammalian cardiomyocyte nuclei are unique due ...

Modeling Stroke in Mice: Permanent Coagulation of the Distal Middle Cerebral Artery

Stroke is the third most common cause of death and a main cause of acquired adult disability in developed countries. Only very limited therapeutical options are available for a small proportion of stroke patients in the acute phase. Current research is intensively searching for novel therapeutic strategies and is increasingly focusing on the sub-acute and chronic phase after stroke because more patients might be eligible for therapeutic interventions in a prolonged time window. These delayed mechanisms include important pathophysiological pathways such as post-stroke inflammation, angiogenesis, neuronal plasticity and regeneration. In order to analyze these mechanisms and to subsequently evaluate novel drug targets, experimental stroke models with clinical relevance, low mortality and high reproducibility are sought after. Moreover, mice are the smallest mammals in which a focal stroke lesion can be induced and for which a broad spectrum of transgenic models are available. Therefore, we describe here the mouse model of transcranial, permanent coagulation of the middle cerebral artery via electrocoagulation distal of the lenticulostriatal arteries, the so-called &#8220;coagulation model&#8221;. The resulting infarct in this model is located mainly in the cortex; the relative infarct volume in relation to brain size corresponds to the majority of human strokes. Moreover, the model fulfills the above-mentioned criteria of reproducibility and low mortality. In this video we demonstrate the surgical methods of stroke induction in the &#8220;coagulation model&#8221; and report histological and functional analysis tools.

Various murine models of middle cerebral artery occlusion (MCAO) are widely used in experimental brain research. Here, we demonstrate the model of transcranial permanent distal MCAO which produces consistent cortical infarction of a size corresponding to damage imposed by the majority of human ischemic strokes.

Stroke is the third most common cause of death and a main cause of acquired adult disability in developed countries. Only very limited therapeutical ...

Multi-electrode Array Recordings of Human Epileptic Postoperative Cortical Tissue

Epilepsy, affecting about 1% of the population, comprises a group of neurological disorders characterized by the periodic occurrence of seizures, which disrupt normal brain function. Despite treatment with currently available antiepileptic drugs targeting neuronal functions, one third of patients with epilepsy are pharmacoresistant. In this condition, surgical resection of the brain area generating seizures remains the only alternative treatment. Studying human epileptic tissues has contributed to understand new epileptogenic mechanisms during the last 10 years. Indeed, these tissues generate spontaneous interictal epileptic discharges as well as pharmacologically-induced ictal events which can be recorded with classical electrophysiology techniques. Remarkably, multi-electrode arrays (MEAs), which are microfabricated devices embedding an array of spatially arranged microelectrodes, provide the unique opportunity to simultaneously stimulate and record field potentials, as well as action potentials of multiple neurons from different areas of the tissue. Thus MEAs recordings offer an excellent approach to study the spatio-temporal patterns of spontaneous interictal and evoked seizure-like events and the mechanisms underlying seizure onset and propagation. Here we describe how to prepare human cortical slices from surgically resected tissue and to record with MEAs interictal and ictal-like events ex vivo.

We here describe how to perform multi-electrode array recordings of human epileptic cortical tissue. Epileptic tissue resection, slice preparation and multi-electrode array recordings of interictal and ictal events are demonstrated in detail.

Epilepsy, affecting about 1% of the population, comprises a group of neurological disorders characterized by the periodic occurrence of seizures, which ...

Use of Ultra-high Field MRI in Small Rodent Models of Polycystic Kidney Disease for In Vivo Phenotyping and Drug Monitoring

Several in vivo pre-clinical studies in Polycystic Kidney Disease (PKD) utilize orthologous rodent models to identify and study the genetic and molecular mechanisms responsible for the disease, and are very convenient for rapid drug screening and testing of promising therapies. A limiting factor in these studies is often the lack of efficient non-invasive methods for sequentially analyzing the anatomical and functional changes in the kidney. Magnetic resonance imaging (MRI) is the current gold standard imaging technique to follow autosomal dominant polycystic kidney disease (ADPKD) patients, providing excellent soft tissue contrast and anatomic detail and allowing Total Kidney Volume (TKV) measurements.A major advantage of MRI in rodent models of PKD is the possibility for in vivo imaging allowing for longitudinal studies that use the same animal and therefore reducing the total number of animals required. In this manuscript, we will focus on using Ultra-high field (UHF) MRI to non-invasively acquire in vivo images of rodent models for PKD. The main goal of this work is to introduce the use of MRI as a tool for in vivo phenotypical characterization and drug monitoring in rodent models for PKD.

Use of Ultra-high Field MRI in Small Rodent Models of Polycystic Kidney Disease for In Vivo Phenotyping and Drug Monitoring

The use of ultra-high field MRI as a non-invasive way to obtain phenotypic information of rodent models for polycystic kidney disease and to monitor interventions is described. Compared with the traditional histological approach, MRI images can be acquired in vivo, allowing for longitudinal follow-up.

Several in vivo pre-clinical studies in Polycystic Kidney Disease (PKD) utilize orthologous rodent models to identify and study the genetic and molecular ...

Hemodynamic Characterization of Rodent Models of Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a rare disease of the pulmonary vasculature characterized by endothelial cell apoptosis, smooth muscle proliferation and obliteration of pulmonary arterioles. This in turn results in right ventricular (RV) failure, with significant morbidity and mortality. Rodent models of PAH, in the mouse and the rat, are important for understanding the pathophysiology underlying this rare disease. Notably, different models of PAH may be associated with different degrees of pulmonary hypertension, RV hypertrophy and RV failure. Therefore, a complete hemodynamic characterization of mice and rats with PAH is critical in determining the effects of drugs or genetic modifications on the disease. 
Here we demonstrate standard procedures for assessment of right ventricular function and hemodynamics in both rat and mouse PAH models. Echocardiography is useful in determining RV function in rats, although obtaining standard views of the right ventricle is challenging in the awake mouse. Access for right heart catheterization is obtained by the internal jugular vein in closed-chest mice and rats. Pressures can be measured using polyethylene tubing with a fluid pressure transducer or a miniature micromanometer pressure catheter. Pressure-volume loop analysis can be performed in the open chest. After obtaining hemodynamics, the rodent is euthanized. The heart can be dissected to separate the RV free wall from the left ventricle (LV) and septum, allowing an assessment of RV hypertrophy using the Fulton index (RV/(LV+S)). Then samples can be harvested from the heart, lungs and other tissues as needed.

Pulmonary arterial hypertension (PAH) is a disease of pulmonary arterioles that leads to their obliteration and the development of right ventricular failure. Rodent models of PAH are critical in understanding the pathophysiology of PAH. Here we demonstrate hemodynamic characterization, with right heart catheterization and echocardiography, in the mouse and rat.

Pulmonary arterial hypertension (PAH) is a rare disease of the pulmonary vasculature characterized by endothelial cell apoptosis, smooth muscle ...

Neurodegeneration in an Animal Model of Chronic Amyloid-beta Oligomer Infusion Is Counteracted by Antibody Treatment Infused with Osmotic Pumps

Decline in hippocampal-dependent explicit memory (memory for facts and events) is one of the earliest clinical symptom of Alzheimer&#39;s disease (AD). It is well established that synapse loss and ensuing neurodegeneration are the best predictors for memory impairments in AD. Latest studies have emphasized the neurotoxic role of soluble amyloid-beta oligomers (A&#946;o) that begin to accumulate in the human brain approximately 10 to 15 yr before the clinical symptoms become apparent. Many reports indicate that soluble A&#946;o correlate with memory deficits in AD models and humans. The A&#946;o-induced neurodegeneration observed in neuronal and brain slice cultures has been more challenging to reproduce in many animal models. The model of repeated A&#946;o infusions shown here overcome this issue and allow addressing two key domains for developing new disease modifying therapies: identify biological markers to diagnose early AD, and determine the molecular mechanisms underpinning A&#946;o-induced memory deficits at the onset of AD. Since soluble A&#946;o aggregate relatively fast into insoluble A&#946; fibrils that correlate poorly with the clinical state of patients, soluble A&#946;o are prepared freshly and injected once per day during six days to produce marked cell death in the hippocampus. We used cannula specially design for simultaneous infusions of A&#946;o and continuous infusion of A&#946;o antibody (6E10) in the hippocampus using osmotic pumps. This innovative in vivo method can now be used in preclinical studies to validate the efficiency of new AD therapies that might prevent the deposition and neurotoxicity of A&#946;o in pre-dementia patients.

To study the effects of A&#946;o in vivo, we developed a model based on repeated hippocampal infusions of soluble A&#946;o coupled with continuous infusion of A&#946;o antibody (6E10) in the hippocampus using osmotic pumps to counteract the neurotoxic effect of A&#946;o.

Decline in hippocampal-dependent explicit memory (memory for facts and events) is one of the earliest clinical symptom of Alzheimer&#39;s disease (AD). It ...

Repeated Measurement of Respiratory Muscle Activity and Ventilation in Mouse Models of Neuromuscular Disease

Accessory respiratory muscles help to maintain ventilation when diaphragm function is impaired. The following protocol describes a method for repeated measurements over weeks or months of accessory respiratory muscle activity while simultaneously measuring ventilation in a non-anesthetized, freely behaving mouse. The technique includes the surgical implantation of a radio transmitter and the insertion of electrode leads into the scalene and trapezius muscles to measure the electromyogram activity of these inspiratory muscles. Ventilation is measured by whole-body plethysmography, and animal movement is assessed by video and is synchronized with electromyogram activity. Measurements of muscle activity and ventilation in a mouse model of amyotrophic lateral sclerosis are presented to show how this tool can be used to investigate how respiratory muscle activity changes over time and to assess the impact of muscle activity on ventilation. The described methods can easily be adapted to measure the activity of other muscles or to assess accessory respiratory muscle activity in additional mouse models of disease or injury.

This paper introduces a method for repeated measurements of ventilation and respiratory muscle activity in a freely behaving amyotrophic lateral sclerosis (ALS) mouse model throughout disease progression with whole-body plethysmography and electromyography via an implanted telemetry device.

Accessory respiratory muscles help to maintain ventilation when diaphragm function is impaired. The following protocol describes a method for repeated ...

Application of Granger Causality Analysis of the Directed Functional Connection in Alzheimer's Disease and Mild Cognitive Impairment

Impaired functional connectivity in the Default Mode Network (DMN) may be involved in the progression of Alzheimer&#39;s Disease (AD). The Posterior Cingulate Cortex (PCC) is a potential imaging marker for monitoring the progression of AD. Previous studies did not focus on the functional connectivity between the PCC and nodes in regions outside the DMN, but our study is an effort to explore these overlooked functional connections. For collecting data, we used functional Magnetic Resonance Imaging (fMRI) and Granger Causality Analysis (GCA). fMRI provides a non-invasive method for studying the dynamic interactions between the different brain regions. GCA is a statistical hypothesis test for determining whether one-time series is useful in forecasting another. In simple terms, it is judged by comparing the &#34;Known all the information on the last moment, the distribution of the probability of X at this time&#34; and the &#34;Known all the information on the last moment except Y, the distribution of the probability of X at this time&#34;, to determine whether there is a causal relationship between Y and X. This definition is based on the complete information source and stationary chronological sequence. The main step of this analysis is to use X and Y to establish the regression equation and draw a causal relationship by a hypothetical test. Since GCA can measure causal effects, we used it to investigate the anisotropy of the functional connectivity and explore the hub function of the PCC. Here, we screened 116 participants for MRI scanning, and after preprocessing the data obtained from neuroimaging, we used GCA to derive the causal relationship of each node. Finally, we concluded that the directed connection is significantly different between the Mild Cognitive Impairment (MCI) and AD groups, both from the PCC to the whole brain and from the whole brain to the PCC.

Application of Granger Causality Analysis of the Directed Functional Connection in Alzheimer&#039;s Disease and Mild Cognitive Impairment

Based on resting-state functional magnetic resonance imaging with Granger causality analysis, we investigated the alterations in the directed functional connectivity between the posterior cingulate cortex and whole brain in patients with Alzheimer&#39;s Disease (AD), patients with Mild Cognitive Impairment (MCI), and healthy controls.

Impaired functional connectivity in the Default Mode Network (DMN) may be involved in the progression of Alzheimer&#39;s Disease (AD). The Posterior ...