Name: sex differences in mouse hippocampal astrocytes after in-vitro ischemia
Uploaded: 2016-10-25T12:30:00
Description: Watch this Scientific Journal Video about Sex Differences in Mouse Hippocampal Astrocytes after In-Vitro Ischemia at JoVE.com

Clinical and Translational Science Award program of NCATS UL1 TR0000427 and KL2 TR000428 (Cengiz P), UL1TR000427 to the UW ICTR from NIH/NCATS and funds from Waisman Center (Cengiz P), K08 NS088563-01A1 from NINDS (Cengiz P) and NIH P30 HD03352 (Waisman Center), NIH/NINDS 1K08NS078113 (Ferrazzano P). We would like to thank Albee Messing, PhD, for providing us the GFAP knockout mice.

NOTE: This study was conducted in accordance with the recommendation of the Guide for the Care and Use of Laboratory Animals of the National Institute of Health. The animal protocol was approved by the University of Wisconsin-Madison, Institutional Animal Care and Use Committee. Primary Astrocyte Culture protocol that is presented here is adopted from the protocols presented by Zhang Y19 et al. and Cengiz P20 et al. with some modifications.
1. Hippocampal Dissection and Astroc...

<ol>
	<li>Powell, E. M., Geller, H. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dissection+of+astrocyte-mediated+cues+in+neuronal+guidance+and+process+extension.">Dissection of astrocyte-mediated cues in neuronal guidance and process extension.</a> Glia. 26, 73-83 (1999).</li><li>Koehler, R. C., Roman, R. J., Harder, D. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Astrocytes+and+the+regulation+of+cerebral+blood+flow.">Astrocytes and the regulation of cerebral blood flow.</a> Trends in neurosciences. 32, 160-169 (2009).</li><li>Seifert, G., Schilling, K., Steinhauser, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Astrocyte+dysfunction+in+neurological+disorders:+a+molecular+perspective.">Astrocyte dysfunction in neurological disorders: a molecular perspective.</a> Nature reviews. Neuroscience. 7, 194-206 (2006).</li><li>Ballabh, P., Braun, A., Nedergaard, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+blood-brain+barrier:+an+overview:+structure,+regulation,+and+clinical+implications.">The blood-brain barrier: an overview: structure, regulation, and clinical implications.</a> Neurobiology of disease. 16, 1-13 (2004).</li><li>Araque, A., Parpura, V., Sanzgiri, R. P., Haydon, P. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tripartite+synapses:+glia,+the+unacknowledged+partner.">Tripartite synapses: glia, the unacknowledged partner.</a> Trends in neurosciences. 22, 208-215 (1999).</li><li>Anderson, M. A., Ao, Y., Sofroniew, M. V. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Heterogeneity+of+reactive+astrocytes.">Heterogeneity of reactive astrocytes.</a> Neuroscience letters. 565, 23-29 (2014).</li><li>Cengiz, P., 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=Inhibition+of+Na+/H++exchanger+isoform+1+is+neuroprotective+in+neonatal+hypoxic+ischemic+brain+injury.">Inhibition of Na+/H+ exchanger isoform 1 is neuroprotective in neonatal hypoxic ischemic brain injury.</a> Antioxidants &amp; redox signaling. 14, 1803-1813 (2011).</li><li>Ferriero, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neonatal+brain+injury.">Neonatal brain injury.</a> The New England journal of medicine. 351, 1985-1995 (2004).</li><li>Hill, C. A., Fitch, R. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sex+differences+in+mechanisms+and+outcome+of+neonatal+hypoxia-ischemia+in+rodent+models:+implications+for+sex-specific+neuroprotection+in+clinical+neonatal+practice.">Sex differences in mechanisms and outcome of neonatal hypoxia-ischemia in rodent models: implications for sex-specific neuroprotection in clinical neonatal practice.</a> Neurol Res Int. , 1-9 (2012).</li><li>Cikla, U., 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=ERalpha+Signaling+Is+Required+for+TrkB-Mediated+Hippocampal+Neuroprotection+in+Female+Neonatal+Mice+after+Hypoxic+Ischemic+Encephalopathy(1,2,3).">ERalpha Signaling Is Required for TrkB-Mediated Hippocampal Neuroprotection in Female Neonatal Mice after Hypoxic Ischemic Encephalopathy(1,2,3).</a> eNeuro. 3, (2016).</li><li>Uluc, K., 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=TrkB+receptor+agonist+7,+8+dihydroxyflavone+triggers+profound+gender-+dependent+neuroprotection+in+mice+after+perinatal+hypoxia+and+ischemia.">TrkB receptor agonist 7, 8 dihydroxyflavone triggers profound gender- dependent neuroprotection in mice after perinatal hypoxia and ischemia.</a> CNS Neurol Disord Drug Targets. 12, 360-370 (2013).</li><li>Cikla, U., 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=Suppression+of+microglia+activation+after+hypoxia-ischemia+results+in+age-dependent+improvements+in+neurologic+injury.">Suppression of microglia activation after hypoxia-ischemia results in age-dependent improvements in neurologic injury.</a> J Neuroimmunol. 291, 18-27 (2016).</li><li>McQuillen, P. S., Ferriero, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Selective+vulnerability+in+the+developing+central+nervous+system.">Selective vulnerability in the developing central nervous system.</a> Pediatr Neurol. 30, 227-235 (2004).</li><li>Morken, T. 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=Altered+astrocyte-neuronal+interactions+after+hypoxia-ischemia+in+the+neonatal+brain+in+female+and+male+rats.">Altered astrocyte-neuronal interactions after hypoxia-ischemia in the neonatal brain in female and male rats.</a> Stroke; a journal of cerebral circulation. 45, 2777-2785 (2014).</li><li>Chisholm, N. C., Sohrabji, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Astrocytic+response+to+cerebral+ischemia+is+influenced+by+sex+differences+and+impaired+by+aging.">Astrocytic response to cerebral ischemia is influenced by sex differences and impaired by aging.</a> Neurobiology of disease. 85, 245-253 (2016).</li><li>Liu, M., Oyarzabal, E. A., Yang, R., Murphy, S. J., Hurn, P. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+novel+method+for+assessing+sex-specific+and+genotype-specific+response+to+injury+in+astrocyte+culture.">A novel method for assessing sex-specific and genotype-specific response to injury in astrocyte culture.</a> Journal of neuroscience methods. 171, 214-217 (2008).</li><li>. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Exploring+the+biological+contributions+to+human+health:+does+sex+matter?.">Exploring the biological contributions to human health: does sex matter?.</a> Journal of women's health &amp; gender-based. 10, 433-439 (2001).</li><li>Collins, F. S., Tabak, L. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Policy:+NIH+plans+to+enhance+reproducibility.">Policy: NIH plans to enhance reproducibility.</a> Nature. 505, 612-613 (2014).</li><li>Zhang, Y., 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+single-step+induction+of+functional+neurons+from+human+pluripotent+stem+cells.">Rapid single-step induction of functional neurons from human pluripotent stem cells.</a> Neuron. 78, 785-798 (2013).</li><li>Cengiz, P., 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=Sustained+Na+/H++exchanger+activation+promotes+gliotransmitter+release+from+reactive+hippocampal+astrocytes+following+oxygen-glucose+deprivation.">Sustained Na+/H+ exchanger activation promotes gliotransmitter release from reactive hippocampal astrocytes following oxygen-glucose deprivation.</a> PloS one. 9, e84294 (2014).</li><li>Landis, S. 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=A+call+for+transparent+reporting+to+optimize+the+predictive+value+of+preclinical+research.">A call for transparent reporting to optimize the predictive value of preclinical research.</a> Nature. 490, 187-191 (2012).</li><li>Hamby, M. E., Uliasz, T. F., Hewett, S. J., Hewett, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+an+improved+procedure+for+the+removal+of+microglia+from+confluent+monolayers+of+primary+astrocytes.">Characterization of an improved procedure for the removal of microglia from confluent monolayers of primary astrocytes.</a> J Neurosci Methods. 150, 128-137 (2006).</li><li>McClive, P. J., Sinclair, A. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+DNA+extraction+and+PCR-sexing+of+mouse+embryos.">Rapid DNA extraction and PCR-sexing of mouse embryos.</a> Molecular reproduction and development. 60, 225-226 (2001).</li><li>Wolterink-Donselaar, I. G., Meerding, J. M., Fernandes, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+method+for+gender+determination+in+newborn+dark+pigmented+mice.">A method for gender determination in newborn dark pigmented mice.</a> Lab Anim (NY). 38, 35-38 (2009).</li><li>Uliasz, T. F., Hamby, M. E., Jackman, N. A., Hewett, J. A., Hewett, S. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generation+of+primary+astrocyte+cultures+devoid+of+contaminating+microglia.">Generation of primary astrocyte cultures devoid of contaminating microglia.</a> Methods Mol Biol. 814, 61-79 (2012).</li><li>Raponi, E., 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=S100B+expression+defines+a+state+in+which+GFAP-expressing+cells+lose+their+neural+stem+cell+potential+and+acquire+a+more+mature+developmental+stage.">S100B expression defines a state in which GFAP-expressing cells lose their neural stem cell potential and acquire a more mature developmental stage.</a> Glia. 55, 165-177 (2007).</li><li>Souza, D. G., Bellaver, B., Souza, D. O., Quincozes-Santos, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Characterization+of+adult+rat+astrocyte+cultures.">Characterization of adult rat astrocyte cultures.</a> PloS one. 8, e60282 (2013).</li><li>Puschmann, T. B., Dixon, K. J., Turnley, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Species+differences+in+reactivity+of+mouse+and+rat+astrocytes+in+vitro.">Species differences in reactivity of mouse and rat astrocytes in vitro.</a> Neuro-Signals. 18, 152-163 (2010).</li><li>Schildge, S., Bohrer, C., Beck, K., Schachtrup, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Isolation+and+culture+of+mouse+cortical+astrocytes.">Isolation and culture of mouse cortical astrocytes.</a> Journal of visualized experiments : JoVE. , (2013).</li><li>Saura, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Microglial+cells+in+astroglial+cultures:+a+cautionary+note.">Microglial cells in astroglial cultures: a cautionary note.</a> J Neuroinflammation. 4 (26), (2007).</li></ol>

In order to study the sex differences in the properties and function of astrocytes under physiological and pathological conditions, preparation of sexed primary astrocytes in cell culture is an important tool to utilize. In the present study we report a highly efficient and a reproducible method to culture a highly enriched homogeneous population of sexed hippocampal astrocytes from newborn (P0-P2) C57Bl/6 (wild type) or K19F (GFAP null) mouse pups in-vitro. Establishing this methodology helps the investigators ...

Astrocytes are one of the most important key players in the central nervous system (CNS). Growing body of evidence indicates that the roles of astrocytes are more than providing&#160;neuronal support. In fact, the roles of astrocytes under physiological conditions can be very complex, such as guiding the migration of the developing axons1, regulating CNS blood flow2, maintaining the pH homeostasis of the synaptic interstitial fluid3, and participating in the blood brain barrier4 and synaptic transmission5. Under pathological conditions, astrocytes respond to injury with a process called reactive astrogliosis in which the morphology, number, location, topography (with respect to distance from insult) and function of the astrocytes may change in a heterogeneous way6,7. Astrogliosis seen following neonatal hypoxic ischemic encephalopathy maybe contributing to the morbidity and mortality of neonates8.
Recent clinical and experimental studies indicate that the severity of brain injury appears to be sex-dependent and that the male neonates are more susceptible to the effects of hypoxia/ischemia (HI)-related brain injury, resulting in more severe neurological outcomes as compared to females with comparable brain injuries9-11. Although the localization of the injury depends on the gestational age and the&#160;duration and the severity of the insult, hippocampus is one of the most commonly effected regions in the CNS after term neonatal HI,&#160;and increased hippocampal astrogliosis has been confirmed by up-regulation of the Glial Fibrillary Acidic Protein (GFAP) 3 d&#160;after the neonatal HI7,10,12,13. Sex differences in astrocyte function were shown in both neonates and adult rodents after cerebral ischemia14,15. In addition, male astrocytic susceptibility to in-vitro ischemia was shown by increased cell death compared to female cortical astrocytes in culture16.
Sex differences start in-utero and continue until death17. Over the last decade, the importance of including the sexes in experimental conditions in cell culture and in-vivo&#160;studies have been the emphasis of the Institute of Medicine and NIH to seek fundamental knowledge in the sex differences seen in physiological and pathological conditions17,18. Development of reliable methods to isolate and maintain populations of sexed hippocampal astrocytes is essential to understand the cellular basis of sex differences in the pathological consequences of neonatal HI. The present study was designed to provide the techniques to prepare enriched sex-specific hippocampal astrocyte cultures from newborn mice in order to assess the roles of GFAP-immunoreactive astrocytes following Oxygen/Glucose Deprivation (OGD) and reoxygenation (REOX),&#160;inducing&#160;HI in cell culture environment. This technique can be used to test any hypothesis pertaining to hippocampal astrocytes in neonatal males and females under normoxic and ischemic conditions.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td colspan="4">Astrocyte culture media</td>
		</tr>
		<tr>
			<td>DMEM, high glucose</td>
			<td>cellgro</td>
			<td>10-013-CV</td>
			<td></td>
		</tr>
		<tr>
			<td>Horse serum</td>
			<td>Gibco</td>
			<td>26050-070</td>
			<td>Final Concentration: 10%</td>
		</tr>
		<tr>
			<td>Penicillin-Streptomycin</td>
			<td>Cellgro&#160;</td>
			<td>30-002-CI</td>
			<td>Final Concentration: 1%</td>
		</tr>
		<tr>
			<td rowspan="2">L-Leucine methyl ester hydrochloride</td>
			<td rowspan="2">Aldrich</td>
			<td rowspan="2">L1002-25G</td>
			<td rowspan="2">Final Concentration: 5 mM</td>
		</tr>
		<tr>
		</tr>
		<tr>
			<td colspan="4">Solution for brain tissue digestion</td>
		</tr>
		<tr>
			<td>HBSS</td>
			<td>Life Technologies</td>
			<td>14170-088</td>
			<td></td>
		</tr>
		<tr>
			<td>0.25% Trypsin</td>
			<td>cellgro</td>
			<td>25-050-CI</td>
			<td>Final Concentration: 0.25%</td>
		</tr>
		<tr>
			<td colspan="4">Other</td>
		</tr>
		<tr>
			<td>70% (vol/vol) ethanol</td>
			<td>Roth</td>
			<td>9065.2</td>
			<td></td>
		</tr>
		<tr>
			<td>Poly-D-Lysine 12mm round coverslips&#160;</td>
			<td>Corning</td>
			<td>354087</td>
			<td></td>
		</tr>
		<tr>
			<td>Water</td>
			<td>Sigma</td>
			<td>W3500</td>
			<td>cell culture grade</td>
		</tr>
		<tr>
			<td>PBS</td>
			<td>cellgro</td>
			<td>21-040-CV</td>
			<td>cell culture grade</td>
		</tr>
		<tr>
			<td>0.05% Trypsin-EDTA&#160;</td>
			<td>Life Technologies</td>
			<td>25300-062</td>
			<td></td>
		</tr>
		<tr>
			<td>70 &#956;m Sterile cell strainer&#160;</td>
			<td>Fisher scientific</td>
			<td>22363548</td>
			<td></td>
		</tr>
		<tr>
			<td>3.5 cm petri dish</td>
			<td>BD Falcon</td>
			<td>353001</td>
			<td></td>
		</tr>
		<tr>
			<td>15 ml Falcon tube</td>
			<td>BD Falcon</td>
			<td>352096</td>
			<td></td>
		</tr>
		<tr>
			<td>50 ml Falcon tube</td>
			<td>BD Falcon</td>
			<td>352070</td>
			<td></td>
		</tr>
		<tr>
			<td>Forceps, fine&#160;</td>
			<td>Dumont</td>
			<td>2-1032; 2-1033</td>
			<td># 3c; # 5</td>
		</tr>
		<tr>
			<td>Forceps, flat tip</td>
			<td>KLS Martin</td>
			<td>12-120-11</td>
			<td></td>
		</tr>
		<tr>
			<td>13 cm surgical scissors</td>
			<td>Aesculap</td>
			<td>BC-140-R</td>
			<td></td>
		</tr>
		<tr>
			<td>Confocal Microscope</td>
			<td>Nikon</td>
			<td>A1RSi&#160;</td>
			<td></td>
		</tr>
		<tr>
			<td>Centrifuge</td>
			<td>Eppendorf</td>
			<td>5805000.017</td>
			<td>Centrifuge5804R</td>
		</tr>
		<tr>
			<td>Orbital Shaker</td>
			<td>Thermo Scientific</td>
			<td>SHKE 4450-1CE</td>
			<td>MaxQ 4450&#160;</td>
		</tr>
		<tr>
			<td>Anti-IBA1</td>
			<td>Wako</td>
			<td>019-19741</td>
			<td>Rabbit monoclonal</td>
		</tr>
		<tr>
			<td>Anti-MAP2</td>
			<td>Sigma</td>
			<td>M2320</td>
			<td>Mouse monoclonal</td>
		</tr>
		<tr>
			<td>Anti-HIF1alpha</td>
			<td>abcam</td>
			<td>ab179483</td>
			<td>rabbit monoclonal</td>
		</tr>
		<tr>
			<td>Anti-S100B</td>
			<td>Sigma</td>
			<td>HPA015768</td>
			<td>Rabbit polyclonal</td>
		</tr>
		<tr>
			<td>Anti-GFAP (cocktail)</td>
			<td>Biolegend</td>
			<td>837602</td>
			<td></td>
		</tr>
		<tr>
			<td>VECTASTAIN Elite ABC Kit (Rabbit IgG)</td>
			<td>Vector Labs</td>
			<td>PK-6101</td>
			<td>Contains 4 Reagents&#160;</td>
		</tr>
		<tr>
			<td>Goat Anti Rabbit Alexa-Fluor 488</td>
			<td>Invitrogen</td>
			<td>A11070</td>
			<td></td>
		</tr>
		<tr>
			<td>Goat Anti Mouse Alexa-Fluor 568</td>
			<td>Invitrogen</td>
			<td>A11004</td>
			<td></td>
		</tr>
	</tbody>
</table>

sex differences in mouse hippocampal astrocytes after in-vitro ischemia

Astrogliosis following hypoxia/ischemia (HI)-related brain injury plays a role in increased morbidity and mortality in neonates. Recent clinical studies indicate that the severity of brain injury appear to be sex dependent, and that the male neonates are more susceptible to the effects of HI-related brain injury, resulting in more severe neurological outcomes as compared to females with comparable brain injuries. The development of reliable methods to isolate and maintain highly enriched populations of sexed hippocampal astrocytes is essential to understand the cellular basis of sex differences in the pathological consequences of neonatal HI. In this study, we describe a method for creating sex specific hippocampal astrocyte cultures that are subjected to a model of in-vitro ischemia, oxygen-glucose deprivation, followed by reoxygenation. Subsequent reactive astrogliosis was examined by immunostaining for the Glial Fibrillary Acidic Protein (GFAP) and S100B. This method provides a useful tool to study the role of male and female hippocampal astrocytes following neonatal HI, separately.

Understanding the roles of sexed astrocyte functions under physiologic or pathophysiological conditions have been immensely elucidated by culturing these cells under in vitro conditions. The important aspect of performing sexed culturing is to determine the sex of the mouse pup prior to its use. We determined the sex of the mouse genetically by PCR and by visual assessment (Figure 2)16. The methodology of sex determination using PCR was adopted with mo...

Watch this Scientific Journal Video about Sex Differences in Mouse Hippocampal Astrocytes after In-Vitro Ischemia at JoVE.com

Sex Differences in Mouse Hippocampal Astrocytes after In-Vitro Ischemia

Astrocytes are one of the most important key players in the central nervous system (CNS). Here, we are reporting a practical method of sexed hippocampal astrocyte culture protocol in order to study the mechanisms underlying the astrocyte function in male and female neonate pups after in-vitro ischemia.

Sex Differences in Mouse Hippocampal Astrocytes after In-Vitro Ischemia

Astrogliosis following hypoxia/ischemia (HI)-related brain injury plays a role in increased morbidity and mortality in neonates. Recent clinical studies ...

The overall goal of this technique is to prepare enriched sex-specific hippocampal astrocyte cultures from newborn mice as a tool to study the sex-specific roles of astrocytes following oxygen and glucose deprivation and reoxygenation in order to mimic in vivo hypoxic ischemia in a cell culture environment. This method can help answer key mechanistic and translational questions pertaining to the sex-specific role of hippocampal astrocytes following hypoxic ischemia in developing male and female brains. Dissect the brain from the head of a newborn mouse pup by using small scissors to create a posterior to anterior midline incision through the skin to expose the cranium.Cut the cranium midline carefully from the neck to the nose. Use sterile flat tip forceps to peel away the skull. Remove the brainstem with the help of curved forceps and place the remaining brain into a dissecting dish.Using curved forceps, flip the brain so that the ventral surface is facing up and then separate the hemispheres with a sharp, sterile surgical blade. With flat curved forceps, peel back the cerebral hemispheres and carefully remove the bulging midbrain and thalamic tissue to reveal the hippocampus, a small seahorse shaped structure in the medial temporal lobe. Remove both the hippocampal lobes and carefully clean the meninges and fibroblasts from the surface of the lobes by pulling with fine forceps.Transfer both hippocampal lobes from a single mouse into a second dish filled with approximately 5 milliliters of HBSS and place on ice. Mince the lobes approximately 4 times using a sharp sterile surgical blade. Use a 1 milliliter sterile pipette to transfer the HBSS and tissue into a 50 milliliter sterile conical tube and then centrifuge at 300 times G for 5 minutes.After centrifugation, aspirate the supernatant. Add 3 milliliters of 0.25 percent trypsin, mix, and incubate the tissue at 37 degrees Celsius for 20 minutes with gentle shaking. Following the incubation, centrifuge the tube at 300 times G for 5 minutes.After the spin, use a sterile glass pipette to carefully aspirate the supernatant and then add 10 milliliters of pre-warmed astrocyte plating medium. Triturate 20 to 30 times using a fire-polished glass pipette. Following another 5 minute centrifugation at 300 times G, aspirate the supernatant and add 2 milliliters of astrocyte plating media.Pass the cell suspension through 70 micron mesh filter into new 50 milliliter conical tube. Add the entire cell suspension to a coated sterile T-25 culture flask containing 3 milliliters of astrocyte plating media. Incubate the flask at 37 degrees Celsius in a 5%carbon dioxide incubator.The next day, observe the progression of astrocytic confluence under a light microscope, aspirate the media and replace with 2 milliliters of fresh astrocyte plating media. Around 11 days in vitro, harvest the confluent astrocytes by aspirating the media and then adding 2 milliliters of 0.25%trypsin. Gently rotate the flask a few times and then aspirate the trypsin using a sterile glass pipette.Add another 2 milliliters of 0.25%trypsin and let the flask sit at room temperature for 4-5 minutes. After removing the trypsin, place the flask at 37 degrees Celsius in a 5%CO2 incubator for 10 minutes. Following the incubation, add 5 milliliters of astrocyte plating medium and detach the astrocytic layer by knocking the flask 3 to 4 times.Gently triturate the cell suspension across the bottom of the flask to achieve complete detachment and then collect the astrocytes in a 15 milliliter conical tube. Centrifuge the tube at 300 times G for 5 minutes. Aspirate the supernatant and then add 1 milliliter of fresh astrocyte plating medium.Add 10 microliters of the cell suspension to a hemocytometer and use an inverted phase contrast microscope with a 10x objective to count the cells in the large central gridded area. Dilute the cells to approximately 1 time 10 to 5th cells per 2 milliliters of astrocyte plating medium. Pipette 2 milliliters of the cell suspension onto a poly-d lysine coated glass coverslip in the well of a 24-well culture dish.Incubate at 37 degrees Celsius in a 5%carbon dioxide incubator. To begin oxygen and glucose deprivation, aspirate the medium from the coverslip containing adherent astrocytes and rinse once with 1 milliliter of isotonic OGD solution. Add 0.2 milliliters of OGD solution to the well and place in a hypoxic incubator.Gently mix with an orbital shaker set to 50 rpm for the first 30 minutes of hypoxia. For reoxygenation, replace the OGD solution with 2 milliliters of astrocyte plating medium and incubate in 5%carbon dioxide and atmospheric air at 37 degrees Celsius for 5 hours. This immunofluorescence image shows the purity of the primary mouse hippocampal astrocyte culture.The astrocyte culture was immunostained to show the neuronal dendrite marker, MAP2, in red, and the microglia marker, IBA1, in green. Nuclei are stained with DAPI which appears blue. The arrow indicates microglia contamination.This representative immunofluorescent image of cultured hippocampal astrocytes under normoxic conditions, shows GFAP immunoreactivity in red and HIF1-alpha labeling in green. Again, nuclei are stained with DAPI which appears blue. The arrow indicates low HIF1-alpha expression.After 2 hours of oxygen and glucose deprivation and 5 hours of reoxygenation, HIF1-alpha expression was increased in cultured hippocampal astrocytes as indicated by the arrowhead indicating elevated HIF1-alpha nuclear expression. GFAP expression and S100b expression were upregulated in hippocampal astrocyte cultures from male mice following oxygen and glucose deprivation and rexoygenation. Upregulation of S100b and GFAP was also seen in astrocytes obtained from female mice.Following this procedure, other methods like quantitative PCR, western blotting, siRNA, and immunohistochemical stainings can be performed in order to answer additional questions like sex-specific changes in certain gene and protein expressions following in vitro ischemia. After it's development, this technique can pave the way for researchers in the field of neuroscience to explore the effects and consequences of stroke in the hippocampus studying the astrocytes in culture.

sex-differences-mouse-hippocampal-astrocytes-after-vitro

Research

JoVE Journal

Neuroscience

Fluorescence Recovery After Photobleaching (FRAP) of Fluorescence Tagged Proteins in Dendritic Spines of Cultured Hippocampal Neurons

FRAP has been used to quantify the mobility of GFP-tagged proteins. Using a strong excitation laser, the fluorescence of a GFP-tagged protein is bleached in the region of interest. The fluorescence of the region recovers when the unbleached GFP-tagged protein from outside of the region diffuses into the region of interest. The mobility of the protein is then analyzed by measuring the fluorescence recovery rate. This technique could be used to characterize protein mobility and turnover rate.
In this study, we express the (enhanced green fluorescent protein) EGFP vector in cultured hippocampal neurons. Using the Zeiss 710 confocal microscope, we photobleach the fluorescence signal of the GFP protein in a single spine, and then take time lapse images to record the fluorescence recovery after photobleaching. Finally, we estimate the percentage of mobile and immobile fractions of the GFP in spines, by analyzing the imaging data using ImageJ and Graphpad softwares.
This FRAP protocol shows how to perform a basic FRAP experiment as well as how to analyze the data.

Fluorescence Recovery After Photobleaching FRAP of Fluorescence Tagged Proteins in Dendritic Spines of Cultured Hippocampal Neurons

FRAP has been used to quantify the mobility of Green Fluorescence Protein (GFP)-tagged proteins in cultured cells. We examined the mobile/immobile fractions of the GFP by analyzing the fluorescence recovery percentage after photobleaching. In this study, FRAP was performed at spines of hippocampal neurons.

FRAP has been used to quantify the mobility of GFP-tagged proteins. Using a strong excitation laser, the fluorescence of a GFP-tagged protein is bleached ...

Dual Electrophysiological Recordings of Synaptically-evoked Astroglial and Neuronal Responses in Acute Hippocampal Slices

Astrocytes form together with neurons tripartite synapses, where they integrate and modulate neuronal activity. Indeed, astrocytes sense neuronal inputs through activation of their ion channels and neurotransmitter receptors, and process information in part through activity-dependent release of gliotransmitters. Furthermore, astrocytes constitute the main uptake system for glutamate, contribute to potassium spatial buffering, as well as to GABA clearance. These cells therefore constantly monitor synaptic activity, and are thereby sensitive indicators for alterations in synaptically-released glutamate, GABA and extracellular potassium levels. Additionally, alterations in astroglial uptake activity or buffering capacity can have severe effects on neuronal functions, and might be overlooked when characterizing physiopathological situations or knockout mice. Dual recording of neuronal and astroglial activities is therefore an important method to study alterations in synaptic strength associated to concomitant changes in astroglial uptake and buffering capacities. Here we describe how to prepare hippocampal slices, how to identify stratum radiatum astrocytes, and how to record simultaneously neuronal and astroglial electrophysiological responses. Furthermore, we describe how to isolate pharmacologically the synaptically-evoked astroglial currents.

The preparation of acute brain slices from isolated hippocampi, as well as the simultaneous electrophysiological recordings of astrocytes and neurons in stratum radiatum during stimulation of schaffer collaterals is described. The pharmacological isolation of astroglial potassium and glutamate transporter currents is demonstrated.

Astrocytes form together with neurons tripartite synapses, where they integrate and modulate neuronal activity. Indeed, astrocytes sense neuronal inputs ...

Isolation and Culture of Mouse Cortical Astrocytes

Astrocytes are an abundant cell type in the mammalian brain, yet much remains to be learned about their molecular and functional characteristics. In vitro astrocyte cell culture systems can be used to study the biological functions of these glial cells in detail. This video protocol shows how to obtain pure astrocytes by isolation and culture of mixed cortical cells of mouse pups. The method is based on the absence of viable neurons and the separation of astrocytes, oligodendrocytes and microglia, the three main glial cell populations of the central nervous system, in culture. Representative images during the first days of culture demonstrate the presence of a mixed cell population and indicate the timepoint, when astrocytes become confluent and should be separated from microglia and oligodendrocytes. Moreover, we demonstrate purity and astrocytic morphology of cultured astrocytes using immunocytochemical stainings for well established and newly described astrocyte markers. This culture system can be easily used to obtain pure mouse astrocytes and astrocyte-conditioned medium for studying various aspects of astrocyte biology.

Astrocytes have been recognized to be versatile cells participating in fundamental biological processes that are essential for normal brain development and function, and central nervous system repair. Here we present a rapid procedure to obtain pure mouse astrocyte cultures to study the biology of this major class of central nervous system cells.

Astrocytes  are an abundant cell type in the mammalian brain, yet much remains to be  learned about their molecular and functional characteristics. In ...

Modeling Astrocytoma Pathogenesis In Vitro and In Vivo Using Cortical Astrocytes or Neural Stem Cells from Conditional, Genetically Engineered Mice

Current astrocytoma models are limited in their ability to define the roles of oncogenic mutations in specific brain cell types during disease pathogenesis and their utility for preclinical drug development. In order to design a better model system for these applications, phenotypically wild-type cortical astrocytes and neural stem cells (NSC) from conditional, genetically engineered mice (GEM) that harbor various combinations of floxed oncogenic alleles were harvested and grown in culture. Genetic recombination was induced in vitro using adenoviral Cre-mediated recombination, resulting in expression of mutated oncogenes and deletion of tumor suppressor genes. The phenotypic consequences of these mutations were defined by measuring proliferation, transformation, and drug response in vitro. Orthotopic allograft models, whereby transformed cells are stereotactically injected into the brains of immune-competent, syngeneic littermates, were developed to define the role of oncogenic mutations and cell type on tumorigenesis in vivo. Unlike most established human glioblastoma cell line xenografts, injection of transformed GEM-derived cortical astrocytes into the brains of immune-competent littermates produced astrocytomas, including the most aggressive subtype, glioblastoma, that recapitulated the histopathological hallmarks of human astrocytomas, including diffuse invasion of normal brain parenchyma. Bioluminescence imaging of orthotopic allografts from transformed astrocytes engineered to express luciferase was utilized to monitor in vivo tumor growth over time. Thus, astrocytoma models using astrocytes and NSC harvested from GEM with conditional oncogenic alleles provide an integrated system to study the genetics and cell biology of astrocytoma pathogenesis in vitro and in vivo and may be useful in preclinical drug development for these devastating diseases.

Modeling Astrocytoma Pathogenesis In Vitro and In Vivo Using Cortical Astrocytes or Neural Stem Cells from Conditional, Genetically Engineered Mice

Phenotypically wild-type astrocytes and neural stem cells harvested from mice engineered with floxed, conditional oncogenic alleles and transformed via viral Cre-mediated recombination can be used to model astrocytoma pathogenesis in vitro and in vivo by orthotopic injection of transformed cells into brains of syngeneic, immune-competent littermates.

Current astrocytoma models are limited in their ability to define the roles of oncogenic mutations in specific brain cell types during disease ...

Immunohistochemical Visualization of Hippocampal Neuron Activity After Spatial Learning in a Mouse Model of Neurodevelopmental Disorders

Induction of phosphorylated extracellular-regulated kinase (pERK) is a reliable molecular readout of learning-dependent neuronal activation. Here, we describe a pERK immunohistochemistry protocol to study the profile of hippocampal neuron activation following exposure to a spatial learning task in a mouse model characterized by cognitive deficits of neurodevelopmental origin. Specifically, we used pERK immunostaining to study neuronal activation following Morris water maze (MWM, a classical hippocampal-dependent learning task) in Engrailed-2 knockout (En2-/-) mice, a model of autism spectrum disorders (ASD). As compared to wild-type (WT) controls, En2-/- mice showed significant spatial learning deficits in the MWM. After MWM, significant differences in the number of pERK-positive neurons were detected in specific hippocampal subfields of En2-/- mice, as compared to WT animals. Thus, our protocol can robustly detect differences in pERK-positive neurons associated to hippocampal-dependent learning impairment in a mouse model of ASD. More generally, our protocol can be applied to investigate the profile of hippocampal neuron activation in both genetic or pharmacological mouse models characterized by cognitive deficits.

We describe an immunohistochemistry protocol to study the profile of hippocampal neuron activation following exposure to a spatial learning task in a mouse model characterized by cognitive deficits of neurodevelopmental origin. This protocol can be applied to both genetic or pharmacological mouse models characterized by cognitive deficits.

Induction of phosphorylated extracellular-regulated kinase (pERK) is a reliable molecular readout of learning-dependent neuronal activation. Here, we ...

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 ...

Tuning in the Hippocampal Theta Band In Vitro: Methodologies for Recording from the Isolated Rodent Septohippocampal Circuit

This protocol outlines the procedures for preparing and recording from the isolated whole hippocampus, of WT and transgenic mice, along with recent improvements in methodologies and applications for the study of theta oscillations. A simple characterization of the isolated hippocampal preparation is presented whereby the relationship between internal hippocampal theta oscillators is examined together with the activity of pyramidal cells, and GABAergic interneurons, of the cornu ammonis-1 (CA1) and subiculum (SUB) areas. Overall, we show that the isolated hippocampus is capable of generating intrinsic theta oscillations in vitro and that rhythmicity generated within the hippocampus can be precisely manipulated by optogenetic stimulation of parvalbumin-positive (PV) interneurons. The in vitro isolated hippocampal preparation offers a unique opportunity to use simultaneous field and intracellular patch-clamp recordings from visually-identified neurons to better understand the mechanisms underlying theta rhythm generation.

Tuning in the Hippocampal Theta Band In Vitro: Methodologies for Recording from the Isolated Rodent Septohippocampal Circuit

Here, we present a protocol for recording rhythmic neuronal network theta and gamma oscillations from an isolated whole hippocampal preparation. We describe the experimental steps from extraction of the hippocampus to details of field, unitary and whole-cell patch clamp recordings as well as optogenetic pacing of the theta rhythm.

This protocol outlines the procedures for preparing and recording from the isolated whole hippocampus, of WT and transgenic mice, along with recent ...

In Utero Electroporation of Multiaddressable Genome-Integrating Color (MAGIC) Markers to Individualize Cortical Mouse Astrocytes

Protoplasmic astrocytes (PrA) located in the mouse cerebral cortex are tightly juxtaposed, forming an apparently continuous three-dimensional matrix at adult stages. Thus far, no immunostaining strategy can single them out and segment their morphology in mature animals and over the course of corticogenesis. Cortical PrA originate from progenitors located in the dorsal pallium and can easily be targeted using in utero electroporation of integrative vectors. A protocol is presented here to label these cells with the multiaddressable genome-integrating color (MAGIC) Markers strategy, which relies on piggyBac/Tol2 transposition and Cre/lox recombination to stochastically express distinct fluorescent proteins (blue, cyan, yellow, and red) addressed to specific subcellular compartments. This multicolor fate mapping strategy enables to mark in situ nearby cortical progenitors with combinations of color markers prior to the start of gliogenesis and to track their descendants, including astrocytes, from embryonic to adult stages at the individual cell level. Semi-sparse labeling achieved by adjusting the concentration of electroporated vectors and color contrasts provided by the Multiaddressable Genome-Integrating Color Markers (MAGIC Markers or MM) enable to individualize astrocytes and single out their territory and complex morphology despite their dense anatomical arrangement. Presented here is a comprehensive experimental workflow including the details of the electroporation procedure, multichannel image stacks acquisition by confocal microscopy, and computer-assisted three-dimensional segmentation that will enable the experimenter to assess individual PrA volume and morphology. In summary, electroporation of MAGIC Markers provides a convenient method to individually label numerous astrocytes and gain access to their anatomical features at different developmental stages. This technique will be useful to analyze cortical astrocyte morphological properties in various mouse models without resorting to complex crosses with transgenic reporter lines.

In Utero Electroporation of Multiaddressable Genome-Integrating Color MAGIC Markers to Individualize Cortical Mouse Astrocytes

Astrocytes tile the cerebral cortex uniformly, making the analysis of their complex morphology challenging at the cellular level. The protocol provided here uses multicolor labeling based on in utero electroporation to single out cortical astrocytes and analyze their volume and morphology with a user-friendly image analysis pipeline.

Protoplasmic astrocytes (PrA) located in the mouse cerebral cortex are tightly juxtaposed, forming an apparently continuous three-dimensional matrix at ...

Neuronal Differentiation from Mouse Embryonic Stem Cells In vitro

The neural differentiation of mouse embryonic stem cells (mESCs) is a potential tool for elucidating the key mechanisms involved in neurogenesis and potentially aid in regenerative medicine. Here, we established an efficient and low cost method for neuronal differentiation from mESCs in vitro, using the strategy of combinatorial screening. Under the conditions defined here, the 2-day embryoid body formation + 6-day retinoic acid induction protocol permits fast and efficient differentiation from mESCs into neural precursor cells (NPCs), as seen by the formation of well-stacked and neurite-like A2lox and 129 derivatives that are Nestin positive. The healthy state of embryoid bodies and the timepoint at which retinoic acid (RA) is applied, as well as the RA concentrations, are critical in the process. In the subsequent differentiation from NPCs into neurons, N2B27 medium II (supplemented by Neurobasal medium) could better support the long term maintenance and maturation of neuronal cells. The presented method is highly efficiency, low cost and easy to operate, and can be a powerful tool for neurobiology and developmental biology research.

Here, we established a low cost and easy to operate method that directs fast and efficient differentiation from embryonic stem cells into neurons. This method is suitable for popularization among laboratories and can be a useful tool for neurological research.

The neural differentiation of mouse embryonic stem cells (mESCs) is a potential tool for elucidating the key mechanisms involved in neurogenesis and ...

Horizontal Hippocampal Slices of the Mouse Brain

The hippocampus is a highly organized structure in the brain that is a part of the limbic system and is involved in memory formation and consolidation as well as the manifestation of severe brain disorders, including Alzheimer&#8217;s disease and epilepsy. The hippocampus receives a high degree of intra- and inter-connectivity, securing a proper communication with internal and external brain structures. This connectivity is accomplished via different informational flows in the form of fiber pathways. Brain slices are a frequently used methodology when exploring neurophysiological functions of the hippocampus. Hippocampal brain slices can be used for several different applications, including electrophysiological recordings, light microscopic measurements as well as several molecular biological and histochemical techniques. Therefore, brain slices represent an ideal model system to assess protein functions, to investigate pathophysiological processes involved in neurological disorders as well as for drug discovery purposes.
There exist several different ways of slice preparations. Brain slice preparations with a vibratome allow a better preservation of the tissue structure and guarantee a sufficient oxygen supply during slicing, which present advantages over the traditional use of a tissue chopper. Moreover, different cutting planes can be applied for vibratome brain slice preparations. Here, a detailed protocol for a successful preparation of vibratome-cut horizontal hippocampal slices of mouse brains is provided. In contrast to other slice preparations, horizontal slicing allows to keep the fibers of the hippocampal input path (perforant path) in a fully intact state within a slice, which facilitates the investigation of entorhinal-hippocampal interactions. Here, we provide a thorough protocol for the dissection, extraction, and acute horizontal slicing of the murine brain, and discuss challenges and potential pitfalls of this technique. Finally, we will show some examples for the use of brain slices in further applications.

This article aims to describe a systematic protocol to obtain horizontal hippocampal brain slices in mice. The objective of this methodology is to preserve the integrity of hippocampal fiber pathways, such as the perforant path and the mossy fiber tract to assess dentate gyrus related neurological processes.

The hippocampus is a highly organized structure in the brain that is a part of the limbic system and is involved in memory formation and consolidation as ...