Name: isolating central nervous system tissues and associated meninges for the downstream analysis of immune cells
Uploaded: 2020-05-19T14:45:00
Description: Watch this Scientific Journal Video about Isolating Central Nervous System Tissues and Associated Meninges for the Downstream Analysis of Immune cells at JoVE.com

The authors thank the staff of the Center for Comparative Medicine and Research (CCMR) at Dartmouth for their expert care of the mice used for these studies. The Bornstein Research Fund funded this research.

All animal work utilizes protocols reviewed and approved by the Institutional Animal Care and Use Committee (IACUC) at Geisel School of Medicine at Dartmouth.
1. Processing brain and spinal cord samples for decalcification
<ol>
	<li>Isolating brain and spinal cord samples
	<ol>
		<li>Euthanize the mouse via CO2 inhalation. Ensure that the CO2 flow rate displaces 10%&#8211;30% of the cage volume per minute.</li>
		<li>Using forceps, lift the xiphoid proc...

Methods for evaluating the cellular composition in the CNS compartment during homeostasis and disease are essential for understanding the physiological and pathological states of the CNS. However, despite serving as an important barrier in the CNS and housing a diverse array of immune cells, the meninges are often omitted from analysis because many conventional tissue extraction methods for the brain and spinal cord do not allow for the collection of these membranes. This omission is a critical limitation in the advancem...

The central nervous system (CNS) is an immunologically specialized site. The CNS parenchyma, excluding the CSF space, the meninges, and the vasculature, is classically viewed as an immune-privileged site1,2,3,4,5 and is relatively devoid of immune cells during homeostatic conditions2,6,7. In contrast, the meninges, comprised of the dura, arachnoid, and pia layers, are crucial components of the CNS compartment, actively participating in homeostatic immune surveillance and inflammatory processes during disease pathogenesis3,6,7,8. During steady state conditions, the meninges support numerous immune sentinel cells, including innate lymphoid cells (ILC), macrophages, dendritic cells (DC), mast cells, T cells, and to a lesser extent, B cells9,10,11.
The meninges are highly vascularized structures and contain lymphatic vessels that provide a lymphatic connection between the CNS and its periphery8,12,13,14. In inflammatory conditions induced by CNS injury, infections, autoimmunity, or even neurodegeneration, peripherally derived immune cells infiltrate the parenchyma and alter the immune landscape within the meninges. Following cell infiltration, the meninges may represent a functional niche for peripherally derived immune cells, promoting immune cell aggregation, local immune cell activation, and long-term survival in the CNS compartment. Prominent meningeal inflammation is observed in multiple diseases affecting the CNS, including multiple sclerosis (MS)15,16,17,18,19, stroke20,21, sterile injury22,23 (i.e., spinal cord injury and traumatic brain injury), migraines24, and microbial infection25,26,27,28,29. Thus, the characterization of resident cells and peripherally derived immune cells in the meningeal compartment is essential for understanding the role of these cells during steady state conditions and disease pathogenesis.
The extraction of the brain, spinal cord, and meninges from the cranium and vertebral bodies is technically challenging and time-consuming. There are currently no techniques available for the rapid extraction of the brain with all three meningeal layers intact. While laminectomy yields excellent spinal cord tissue morphology and preserves the meningeal layers, it is both extremely time-consuming and complicated30,31. Conversely, more conventional extraction methods such as the removal of the brain from the cranium and the hydraulic extrusion of the spinal cord facilitate the quick extraction of the CNS tissue, but both the arachnoid and dural meninges are lost with these techniques30,31. The omission of dura and arachnoid layers during conventional isolation of brain and spinal cord tissues results in an incomplete analysis of the cells within the CNS compartment. Thus, the identification of new techniques focused on the quick extraction of CNS tissues with intact meninges is crucial for the optimal analysis of the CNS compartment.
This manuscript presents two methods for the rapid extraction of the brain, spinal cord, and meninges from mice, facilitating the downstream analysis of resident cells and peripherally derived immune cells in the CNS parenchyma and meninges. These optimized protocols focus on 1) isolating single-cell suspensions for downstream analysis and 2) preparing tissue for histological processing. Obtaining single-cell suspensions from the brain, spinal cord tissue, and dural and arachnoid meninges32 allows for the simultaneous analysis of cells residing in both the parenchymal and meningeal compartments. Single-cell suspensions can be used in different applications, including cell culture assays to perform in vitro stimulation33, enzyme-linked immunospot (ELISpot)28,34,35, flow cytometry36,33, and single-cell37 or bulk transcriptomics. Additionally, the optimized protocol for decalcification of whole brains and spinal cords with intact skulls or vertebral columns, respectively, allows for the gentle decalcification of the surrounding bone, leaving the meninges intact and preserving the tissue morphology. This method allows for the selective identification of proteins or RNA using immunohistochemistry (IHC) or in situ hybridization (ISH) techniques within both the parenchymal and meningeal spaces. The characterization of the phenotype, activation state, and localization of resident cells and peripherally derived immune cells within the CNS may provide information essential to understanding how individual cell types in the CNS compartment contribute to homeostasis and disease pathogenesis.

<table>
	<tbody>
		<tr>
			<td>Aluminum foil</td>
			<td>any</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>Bovine Serum Albumin</td>
			<td>ThermoFisher Scientific</td>
			<td>37002D</td>
			<td></td>
		</tr>
		<tr>
			<td>Centrifuge</td>
			<td>Beckman Coulter</td>
			<td>Allegra X-12R centrifuge</td>
			<td></td>
		</tr>
		<tr>
			<td>Collagenase I</td>
			<td>Worthington</td>
			<td>LS004196</td>
			<td></td>
		</tr>
		<tr>
			<td>Conical tube, 15 mL</td>
			<td>VWR</td>
			<td>525-1069</td>
			<td></td>
		</tr>
		<tr>
			<td>Conical tube, 50 mL</td>
			<td>VWR</td>
			<td>89039-658</td>
			<td></td>
		</tr>
		<tr>
			<td>Cover glass</td>
			<td>Hauser Scientific</td>
			<td>5000</td>
			<td></td>
		</tr>
		<tr>
			<td>Cryomold</td>
			<td>VWR</td>
			<td>18000-128</td>
			<td></td>
		</tr>
		<tr>
			<td>Curved forceps</td>
			<td>Fine Science Tools</td>
			<td>11003-14</td>
			<td></td>
		</tr>
		<tr>
			<td>Disposable polystyrene tube, 14 mL</td>
			<td>Fisher Scientific</td>
			<td>14-959-1B</td>
			<td></td>
		</tr>
		<tr>
			<td>Disposable Scalpel</td>
			<td>Fisher Scientific</td>
			<td>NC0595256</td>
			<td></td>
		</tr>
		<tr>
			<td>DNAse I</td>
			<td>Worthington</td>
			<td>LS002139</td>
			<td></td>
		</tr>
		<tr>
			<td>Dry ice</td>
			<td>Airgas</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>Durmont #7Forceps</td>
			<td>Fine Science Tools</td>
			<td>11271-30</td>
			<td></td>
		</tr>
		<tr>
			<td>EDTA disodium salt dihydrate</td>
			<td>Amresco</td>
			<td>0105-500g</td>
			<td></td>
		</tr>
		<tr>
			<td>Ethanol, 100%</td>
			<td>any</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>Fetal Bovine Serum (FBS)</td>
			<td>Hyclone</td>
			<td>SH30910.03</td>
			<td></td>
		</tr>
		<tr>
			<td>Filter top tube, 5 mL</td>
			<td>VWR</td>
			<td>352235</td>
			<td></td>
		</tr>
		<tr>
			<td>Fixable viability stain 780</td>
			<td>Becton Dickinson</td>
			<td>565388</td>
			<td></td>
		</tr>
		<tr>
			<td>Flow cytometer</td>
			<td>Beckman Coulter</td>
			<td>Gallios</td>
			<td></td>
		</tr>
		<tr>
			<td>Glucose</td>
			<td>Fisher Chemical</td>
			<td>D16-500</td>
			<td></td>
		</tr>
		<tr>
			<td>Goat anti-mouse IgG (488 conjugate)</td>
			<td>Jackson immunoresearch</td>
			<td>115-546-146</td>
			<td></td>
		</tr>
		<tr>
			<td>Goat anti-mouse IgG (594 conjugate)</td>
			<td>Jackson immunoresearch</td>
			<td>115-586-146</td>
			<td></td>
		</tr>
		<tr>
			<td>Goat anti-rabbit 488</td>
			<td>Jackson immunoresearch</td>
			<td>111-545-144</td>
			<td></td>
		</tr>
		<tr>
			<td>Goat anti-rat 594</td>
			<td>Jackson immunoresearch</td>
			<td>112-585-167</td>
			<td></td>
		</tr>
		<tr>
			<td>Goat anti-rat 650</td>
			<td>Jackson immunoresearch</td>
			<td>112-605-167</td>
			<td></td>
		</tr>
		<tr>
			<td>Hank&#39;s Balnced Salt Solution (HBSS)</td>
			<td>Corning</td>
			<td>21-020-CV</td>
			<td></td>
		</tr>
		<tr>
			<td>Hemacytometer</td>
			<td>Andwin Scientific</td>
			<td>02-671-51B</td>
			<td></td>
		</tr>
		<tr>
			<td>Hemostat</td>
			<td>Fine Science Tools</td>
			<td>13004-14</td>
			<td></td>
		</tr>
		<tr>
			<td>HEPES (N-2-hydroxyethylpiperazine-N-2-ethane sulfonic acid)</td>
			<td>ThermoFisher Scientific</td>
			<td>15630080</td>
			<td></td>
		</tr>
		<tr>
			<td>KCl</td>
			<td>Fisher chemical</td>
			<td>BP366-500</td>
			<td></td>
		</tr>
		<tr>
			<td>KH2PO4 (anhydrous)</td>
			<td>Sigma Aldrich</td>
			<td>P5655-100G</td>
			<td></td>
		</tr>
		<tr>
			<td>Liquid Nitrogen</td>
			<td>Airgas</td>
			<td>N/A</td>
			<td></td>
		</tr>
		<tr>
			<td>Mouse FC block (CD16/32)</td>
			<td>Becton Dickinson</td>
			<td>553141</td>
			<td></td>
		</tr>
		<tr>
			<td>Na2HP04 (anhydrous)</td>
			<td>Fisher Chemical</td>
			<td>S374-500</td>
			<td></td>
		</tr>
		<tr>
			<td>NaCl</td>
			<td>Fisher chemical</td>
			<td>S671-500</td>
			<td></td>
		</tr>
		<tr>
			<td>Needle, 25 gauge</td>
			<td>Becton Dickinson</td>
			<td>305122</td>
			<td></td>
		</tr>
		<tr>
			<td>Normal mouse serum</td>
			<td>ThermoFisher Scientific</td>
			<td>31881</td>
			<td></td>
		</tr>
		<tr>
			<td>Nylon mesh strainer</td>
			<td>VWR</td>
			<td>352350</td>
			<td></td>
		</tr>
		<tr>
			<td>OCT</td>
			<td>Sakura</td>
			<td>4583</td>
			<td></td>
		</tr>
		<tr>
			<td>Paraformaldehyde, 20%</td>
			<td>Electron Microscopy Sciences</td>
			<td>15713-S</td>
			<td>Diluted to 4% using 1 x PBS</td>
		</tr>
		<tr>
			<td>Pasteur pipette, 9 inch, unplugged</td>
			<td>Fisher Scientific</td>
			<td>13-678-20C</td>
			<td></td>
		</tr>
		<tr>
			<td>PBS (1x)</td>
			<td>Corning</td>
			<td>21-040-CV</td>
			<td></td>
		</tr>
		<tr>
			<td>PE Rat Anti-Mouse CD4</td>
			<td>Becton Dickinson</td>
			<td>553730</td>
			<td></td>
		</tr>
		<tr>
			<td>PE-CF594 Rat Anti-Mouse CD19</td>
			<td>Becton Dickinson</td>
			<td>562329</td>
			<td></td>
		</tr>
		<tr>
			<td>Percoll density gradient media</td>
			<td>GE healthcare</td>
			<td>17-0891-01</td>
			<td></td>
		</tr>
		<tr>
			<td>PerCP-Cy5.5 Rat Anti-Mouse CD45</td>
			<td>Becton Dickinson</td>
			<td>550994</td>
			<td></td>
		</tr>
		<tr>
			<td>Petri dish, 100 mm</td>
			<td>VWR</td>
			<td>353003</td>
			<td></td>
		</tr>
		<tr>
			<td>pH meter</td>
			<td>Fisher Scientific</td>
			<td>13-636-AB150</td>
			<td></td>
		</tr>
		<tr>
			<td>Pipet-Aid</td>
			<td>Drummond Scientific Corporation</td>
			<td>4-000-101</td>
			<td></td>
		</tr>
		<tr>
			<td>Pipette 200 &#181;l</td>
			<td>Gilson</td>
			<td>FA10005M</td>
			<td></td>
		</tr>
		<tr>
			<td>Pipette tips, 1 mL</td>
			<td>USA Scientific</td>
			<td>1111-2831</td>
			<td></td>
		</tr>
		<tr>
			<td>Pipette tips, 200 &#181;l</td>
			<td>USA Scientific</td>
			<td>1111-1816</td>
			<td></td>
		</tr>
		<tr>
			<td>Pipette, 1 mL</td>
			<td>Gilson</td>
			<td>FA10006M</td>
			<td></td>
		</tr>
		<tr>
			<td>Prolong Diamond mountant with DAPI</td>
			<td>ThermoFisher Scientific</td>
			<td>P36962</td>
			<td></td>
		</tr>
		<tr>
			<td>Purified Rat Anti-Mouse CD16/CD32</td>
			<td>Becton Dickinson</td>
			<td>553141</td>
			<td></td>
		</tr>
		<tr>
			<td>Rabbit anti-mouse CD3 (SP7 clone)</td>
			<td>Abcam</td>
			<td>ab16669</td>
			<td></td>
		</tr>
		<tr>
			<td>Rabbit anti-mouse laminin</td>
			<td>Abcam</td>
			<td>ab11575</td>
			<td></td>
		</tr>
		<tr>
			<td>Rat anti-mouse ERT-R7</td>
			<td>Abcam</td>
			<td>ab51824</td>
			<td></td>
		</tr>
		<tr>
			<td>RPMI 1640</td>
			<td>Corning</td>
			<td>10-040-CV</td>
			<td></td>
		</tr>
		<tr>
			<td>Serological pipet, 1 mL</td>
			<td>VWR</td>
			<td>357521</td>
			<td></td>
		</tr>
		<tr>
			<td>Serological pipet, 10 mL</td>
			<td>VWR</td>
			<td>357551</td>
			<td></td>
		</tr>
		<tr>
			<td>Serological pipet, 5 mL</td>
			<td>VWR</td>
			<td>357543</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium hydroxide</td>
			<td>Fisher Scientific</td>
			<td>S318-100</td>
			<td></td>
		</tr>
		<tr>
			<td>Sucrose</td>
			<td>Fisher chemical</td>
			<td>S5-500</td>
			<td></td>
		</tr>
		<tr>
			<td>Surgical scissors</td>
			<td>Fine Science Tools</td>
			<td>14001-16</td>
			<td></td>
		</tr>
		<tr>
			<td>Surgical scissors, extra fine</td>
			<td>Roboz</td>
			<td>RS-5882</td>
			<td></td>
		</tr>
		<tr>
			<td>Syringe, 10 mL</td>
			<td>Becton Dickinson</td>
			<td>302995</td>
			<td></td>
		</tr>
		<tr>
			<td>Syringe, 5 mL</td>
			<td>Becton Dickinson</td>
			<td>309646</td>
			<td></td>
		</tr>
		<tr>
			<td>Trypan blue</td>
			<td>Gibco</td>
			<td>15250-061</td>
			<td></td>
		</tr>
		<tr>
			<td>Vacuum filter system</td>
			<td>Millipore</td>
			<td>20207749</td>
			<td></td>
		</tr>
		<tr>
			<td>Vacuum flask</td>
			<td>Thomas Scientific</td>
			<td>5340-2L</td>
			<td></td>
		</tr>
		<tr>
			<td>Vacuum in-line filter</td>
			<td>Pall Corporation</td>
			<td>4402</td>
			<td></td>
		</tr>
		<tr>
			<td>Vacuum line</td>
			<td>Cole Palmer</td>
			<td>EW-06414-20</td>
			<td></td>
		</tr>
		<tr>
			<td>Water bath</td>
			<td>ThermoFisher Scientific</td>
			<td>Versa bath</td>
			<td></td>
		</tr>
	</tbody>
</table>

isolating central nervous system tissues and associated meninges for the downstream analysis of immune cells

The central nervous system (CNS) is comprised of the brain and spinal cord and is enveloped by the meninges, membranous layers serving as a barrier between the periphery and the CNS. The CNS is an immunologically specialized site, and in steady state conditions, immune privilege is most evident in the CNS parenchyma. In contrast, the meninges harbor a diverse array of resident cells, including innate and adaptive immune cells. During inflammatory conditions triggered by CNS injury, autoimmunity, infection, or even neurodegeneration, peripherally derived immune cells may enter the parenchyma and take up residence within the meninges. These cells are thought to perform both beneficial and detrimental actions during CNS disease pathogenesis. Despite this knowledge, the meninges are often overlooked when analyzing the CNS compartment, because conventional CNS tissue extraction methods omit the meningeal layers. This protocol presents two distinct methods for the rapid isolation of murine CNS tissues (i.e., brain, spinal cord, and meninges) that are suitable for downstream analysis via single-cell techniques, immunohistochemistry, and in situ hybridization methods. The described methods provide a comprehensive analysis of CNS tissues, ideal for assessing the phenotype, function, and localization of cells occupying the CNS compartment under homeostatic conditions and during disease pathogenesis.

This representative experiment was aimed at quantifying B and T cells and describing B and T cell localization in the meningeal and parenchymal CNS compartments in homeostatic conditions as well as in a murine progressive MS model (i.e., TMEV-IDD). TMEV-IDD was induced in 5-week-old female SJL mice by intracranial infection with 5 x 106 plaque forming units (PFU) of TMEV BeAn as previously described29.
The present study assessed B and T cells in the meninges,...

Watch this Scientific Journal Video about Isolating Central Nervous System Tissues and Associated Meninges for the Downstream Analysis of Immune cells at JoVE.com

Isolating Central Nervous System Tissues and Associated Meninges for the Downstream Analysis of Immune cells

This paper presents two optimized protocols for examining resident and peripherally derived immune cells within the central nervous system, including the brain, spinal cord, and meninges. Each of these protocols helps to ascertain the function and composition of the cells occupying these compartments under steady state and inflammatory conditions.

The central nervous system (CNS) is comprised of the brain and spinal cord and is enveloped by the meninges, membranous layers serving as a barrier ...

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